Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain
Identifieur interne : 000842 ( Istex/Corpus ); précédent : 000841; suivant : 000843Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain
Auteurs : Lydie Ngandu ; Dominique Robin ; Asma El Kasmi ; Doris LexaSource :
- Inorganica Chimica Acta [ 0020-1693 ] ; 1999.
English descriptors
- KwdEn :
- B12a, Co(III)balamin, B12r, Co(II)balamin, B12s, Co(I)balamin, BR, Britton–Robinson, Bzm, benzimidazole, CV, cyclic voltammetry, Cbi, cobinamide, Cbl, cobalamin, Cobalamins, EPG, edge plane pyrolytic graphite, Electrochemistry, GC, glassy carbon, GSH, reduced glutathione, IF, intrinsic factor, NIF, non-intrinsic factor, SCE, saturated calomel electrode, Vitamin B12 derivatives.
Abstract
Several vitamin B12 derivatives (aquo, acetato, and glutathionyl cobalamins) adsorbed on an edge pyrolytic graphite electrode are studied in order to determine how their electrochemical behaviors are influenced by either the direct adsorption on the electrode material, or the adsorption in the presence of transport proteins, intrinsic factor (IF) and non-intrinsic factor (NIF). Comparison with the interfacial electrochemistry of the cobinamide demonstrates that, at neutral pH, the benzimidazole (Bzm) moiety is still coordinated to the Co(III) and Co(II) oxidized states of the adsorbed cobalamins. On the other hand, adsorption on pyrolytic graphite electrodes is shown to accelerate the kinetics for the reduction Co(III)/Co(II) when strong coordination by glutathione is involved compared to the results obtained in solution. The transport protein–cobalamin complexes are still reducible on the electrode. The potentials are not really changed for the IF complex while Co(II) is slightly more difficult to reduce in the case of the NIF complex.
Url:
DOI: 10.1016/S0020-1693(99)00193-0
Links to Exploration step
ISTEX:C6DA6EA095A3203E58EC06107FF215D9BF99D781Le document en format XML
<record><TEI wicri:istexFullTextTei="biblStruct"><teiHeader><fileDesc><titleStmt><title xml:lang="en">Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</title><author><name sortKey="Ngandu, Lydie" sort="Ngandu, Lydie" uniqKey="Ngandu L" first="Lydie" last="Ngandu">Lydie Ngandu</name><affiliation><mods:affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</mods:affiliation></affiliation></author><author><name sortKey="Robin, Dominique" sort="Robin, Dominique" uniqKey="Robin D" first="Dominique" last="Robin">Dominique Robin</name><affiliation><mods:affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</mods:affiliation></affiliation></author><author><name sortKey="El Kasmi, Asma" sort="El Kasmi, Asma" uniqKey="El Kasmi A" first="Asma" last="El Kasmi">Asma El Kasmi</name><affiliation><mods:affiliation>School of Science and Engineering, Al Akhawayn University, PO Box 104, A. Hassan II, Ifrane 53000, Morocco</mods:affiliation></affiliation></author><author><name sortKey="Lexa, Doris" sort="Lexa, Doris" uniqKey="Lexa D" first="Doris" last="Lexa">Doris Lexa</name><affiliation><mods:affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</mods:affiliation></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">ISTEX</idno><idno type="RBID">ISTEX:C6DA6EA095A3203E58EC06107FF215D9BF99D781</idno><date when="1999" year="1999">1999</date><idno type="doi">10.1016/S0020-1693(99)00193-0</idno><idno type="url">https://api.istex.fr/document/C6DA6EA095A3203E58EC06107FF215D9BF99D781/fulltext/pdf</idno><idno type="wicri:Area/Istex/Corpus">000842</idno><idno type="wicri:explorRef" wicri:stream="Istex" wicri:step="Corpus" wicri:corpus="ISTEX">000842</idno></publicationStmt><sourceDesc><biblStruct><analytic><title level="a" type="main" xml:lang="en">Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</title><author><name sortKey="Ngandu, Lydie" sort="Ngandu, Lydie" uniqKey="Ngandu L" first="Lydie" last="Ngandu">Lydie Ngandu</name><affiliation><mods:affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</mods:affiliation></affiliation></author><author><name sortKey="Robin, Dominique" sort="Robin, Dominique" uniqKey="Robin D" first="Dominique" last="Robin">Dominique Robin</name><affiliation><mods:affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</mods:affiliation></affiliation></author><author><name sortKey="El Kasmi, Asma" sort="El Kasmi, Asma" uniqKey="El Kasmi A" first="Asma" last="El Kasmi">Asma El Kasmi</name><affiliation><mods:affiliation>School of Science and Engineering, Al Akhawayn University, PO Box 104, A. Hassan II, Ifrane 53000, Morocco</mods:affiliation></affiliation></author><author><name sortKey="Lexa, Doris" sort="Lexa, Doris" uniqKey="Lexa D" first="Doris" last="Lexa">Doris Lexa</name><affiliation><mods:affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</mods:affiliation></affiliation></author></analytic><monogr></monogr><series><title level="j">Inorganica Chimica Acta</title><title level="j" type="abbrev">ICA</title><idno type="ISSN">0020-1693</idno><imprint><publisher>ELSEVIER</publisher><date type="published" when="1999">1999</date><biblScope unit="volume">292</biblScope><biblScope unit="issue">2</biblScope><biblScope unit="page" from="204">204</biblScope><biblScope unit="page" to="212">212</biblScope></imprint><idno type="ISSN">0020-1693</idno></series><idno type="istex">C6DA6EA095A3203E58EC06107FF215D9BF99D781</idno><idno type="DOI">10.1016/S0020-1693(99)00193-0</idno><idno type="PII">S0020-1693(99)00193-0</idno></biblStruct></sourceDesc><seriesStmt><idno type="ISSN">0020-1693</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>B12a, Co(III)balamin</term><term>B12r, Co(II)balamin</term><term>B12s, Co(I)balamin</term><term>BR, Britton–Robinson</term><term>Bzm, benzimidazole</term><term>CV, cyclic voltammetry</term><term>Cbi, cobinamide</term><term>Cbl, cobalamin</term><term>Cobalamins</term><term>EPG, edge plane pyrolytic graphite</term><term>Electrochemistry</term><term>GC, glassy carbon</term><term>GSH, reduced glutathione</term><term>IF, intrinsic factor</term><term>NIF, non-intrinsic factor</term><term>SCE, saturated calomel electrode</term><term>Vitamin B12 derivatives</term></keywords></textClass><langUsage><language ident="en">en</language></langUsage></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">Several vitamin B12 derivatives (aquo, acetato, and glutathionyl cobalamins) adsorbed on an edge pyrolytic graphite electrode are studied in order to determine how their electrochemical behaviors are influenced by either the direct adsorption on the electrode material, or the adsorption in the presence of transport proteins, intrinsic factor (IF) and non-intrinsic factor (NIF). Comparison with the interfacial electrochemistry of the cobinamide demonstrates that, at neutral pH, the benzimidazole (Bzm) moiety is still coordinated to the Co(III) and Co(II) oxidized states of the adsorbed cobalamins. On the other hand, adsorption on pyrolytic graphite electrodes is shown to accelerate the kinetics for the reduction Co(III)/Co(II) when strong coordination by glutathione is involved compared to the results obtained in solution. The transport protein–cobalamin complexes are still reducible on the electrode. The potentials are not really changed for the IF complex while Co(II) is slightly more difficult to reduce in the case of the NIF complex.</div></front></TEI><istex><corpusName>elsevier</corpusName><author><json:item><name>Lydie Ngandu</name><affiliations><json:string>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</json:string></affiliations></json:item><json:item><name>Dominique Robin</name><affiliations><json:string>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</json:string></affiliations></json:item><json:item><name>Asma El Kasmi</name><affiliations><json:string>School of Science and Engineering, Al Akhawayn University, PO Box 104, A. Hassan II, Ifrane 53000, Morocco</json:string></affiliations></json:item><json:item><name>Doris Lexa</name><affiliations><json:string>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</json:string></affiliations></json:item></author><subject><json:item><lang><json:string>eng</json:string></lang><value>Vitamin B12 derivatives</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Cobalamins</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Electrochemistry</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Cbl, cobalamin</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>B12a, Co(III)balamin</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>B12r, Co(II)balamin</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>B12s, Co(I)balamin</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Cbi, cobinamide</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>Bzm, benzimidazole</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>GSH, reduced glutathione</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>IF, intrinsic factor</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>NIF, non-intrinsic factor</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>CV, cyclic voltammetry</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>EPG, edge plane pyrolytic graphite</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>GC, glassy carbon</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>BR, Britton–Robinson</value></json:item><json:item><lang><json:string>eng</json:string></lang><value>SCE, saturated calomel electrode</value></json:item></subject><language><json:string>eng</json:string></language><originalGenre><json:string>Full-length article</json:string></originalGenre><abstract>Several vitamin B12 derivatives (aquo, acetato, and glutathionyl cobalamins) adsorbed on an edge pyrolytic graphite electrode are studied in order to determine how their electrochemical behaviors are influenced by either the direct adsorption on the electrode material, or the adsorption in the presence of transport proteins, intrinsic factor (IF) and non-intrinsic factor (NIF). Comparison with the interfacial electrochemistry of the cobinamide demonstrates that, at neutral pH, the benzimidazole (Bzm) moiety is still coordinated to the Co(III) and Co(II) oxidized states of the adsorbed cobalamins. On the other hand, adsorption on pyrolytic graphite electrodes is shown to accelerate the kinetics for the reduction Co(III)/Co(II) when strong coordination by glutathione is involved compared to the results obtained in solution. The transport protein–cobalamin complexes are still reducible on the electrode. The potentials are not really changed for the IF complex while Co(II) is slightly more difficult to reduce in the case of the NIF complex.</abstract><qualityIndicators><score>6.824</score><pdfVersion>1.2</pdfVersion><pdfPageSize>552 x 770 pts</pdfPageSize><refBibsNative>true</refBibsNative><keywordCount>17</keywordCount><abstractCharCount>1052</abstractCharCount><pdfWordCount>5132</pdfWordCount><pdfCharCount>29159</pdfCharCount><pdfPageCount>9</pdfPageCount><abstractWordCount>152</abstractWordCount></qualityIndicators><title>Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</title><pii><json:string>S0020-1693(99)00193-0</json:string></pii><genre><json:string>research-article</json:string></genre><host><volume>292</volume><pii><json:string>S0020-1693(00)X0093-X</json:string></pii><pages><last>212</last><first>204</first></pages><issn><json:string>0020-1693</json:string></issn><issue>2</issue><genre><json:string>journal</json:string></genre><language><json:string>unknown</json:string></language><title>Inorganica Chimica Acta</title><publicationDate>1999</publicationDate></host><categories><wos><json:string>CHEMISTRY, INORGANIC & NUCLEAR</json:string></wos></categories><publicationDate>1999</publicationDate><copyrightDate>1999</copyrightDate><doi><json:string>10.1016/S0020-1693(99)00193-0</json:string></doi><id>C6DA6EA095A3203E58EC06107FF215D9BF99D781</id><score>0.085829705</score><fulltext><json:item><original>true</original><mimetype>application/pdf</mimetype><extension>pdf</extension><uri>https://api.istex.fr/document/C6DA6EA095A3203E58EC06107FF215D9BF99D781/fulltext/pdf</uri></json:item><json:item><original>false</original><mimetype>application/zip</mimetype><extension>zip</extension><uri>https://api.istex.fr/document/C6DA6EA095A3203E58EC06107FF215D9BF99D781/fulltext/zip</uri></json:item><istex:fulltextTEI uri="https://api.istex.fr/document/C6DA6EA095A3203E58EC06107FF215D9BF99D781/fulltext/tei"><teiHeader><fileDesc><titleStmt><title level="a" type="main" xml:lang="en">Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</title></titleStmt><publicationStmt><authority>ISTEX</authority><publisher>ELSEVIER</publisher><availability><p>©1999 Elsevier Science S.A.</p></availability><date>1999</date></publicationStmt><notesStmt><note type="content">Fig. 1: (A) Structures of vitamin B12 derivatives in the base-on form (L=H2O, OH−, glutathionyl, acetato). (B) Diaquocobinamide, (L=H2O).</note><note type="content">Fig. 2: CV in pH 5.06 BR buffer on coated pyrolytic graphite electrode. (A) First scan, starting potential +0.6 to −1.1 V; v=200 mV s−1; 20°C; solid line, hydroxoCbl; dashed line, acetatoCbl. (B) Variation of the reduction waves of acetatoCbl adsorbed on pyrolytic graphite electrode with the pH in BR buffer; v=200 mV s−1, 20°C. Second and others scans at solid line, pH 2, dotted line, pH 5, dashed line, pH 9.</note><note type="content">Fig. 3: CV in pH 5.06 BR buffer of (A) acetatoCbl adsorbed on pyrolytic graphite electrode; variations with the sweep rate: v=50, 150, 200 mV s−1. (B) DiaquoCbi adsorbed on pyrolytic graphite electrode at the same pH. Starting potential: −0.3 V; variation with the sweep rate, v=50, 100, 200 mV s−1.</note><note type="content">Scheme 1:</note><note type="content">Scheme 2:</note><note type="content">Scheme 3:</note><note type="content">Fig. 4: CV in a solution pH 6.36 of BR buffer, on a glassy carbon electrode; v=200 mV s−1; titration with glutathione: (A) solid line, aquoCbl (c=2.3×10−3 M l−1); dashed line, +GSH (c=1.6× 10−3 M l−1); dotted line, +GSH (c=2.3×10−3 M l−1). (B) GSHCbl in the same solution: variation with the sweep rate: dotted line, v=20; dashed line, v=50; solid line, v=100 mV s−1.</note><note type="content">Fig. 5: CV of aquocobalamin adsorbed on EPG in pH 5.7 BR buffer, v=100 mV s−1: (A) solid line, aquobalamin; dashed line, +10−2 M l−1 glutathione; (B) after several scans: solid line, starting +0.5 to −1 V; dashed line, starting −0.9 to +0.5 V.</note><note type="content">Fig. 6: Optical study of the complexation of B12r prepared by preparative electrolysis in pH 5.7 BR buffer; optical path cell, 0.2 cm. (a) Solid line, spectrum of B12r (c=2.96×10−4 M l−1), (b) dashed line, spectrum evolution after the adduct of glutathione (3×10−1 M l−1).</note><note type="content">Fig. 7: CV of acetatocobalamin on EPG in pH 7 BR buffer, v=200 mV s−1: solid line, acetatoCbl (1×10−12 mol mm−2 deposited); dotted line, IF+acetatoCbl (0.2 units+1.5×10−12 mol mm−2 deposited).</note><note type="content">Table 1:</note><note type="content">Table 2: Formal potentials of aquo- and glutathionyl-cobalamin at pH 5.7</note></notesStmt><sourceDesc><biblStruct type="inbook"><analytic><title level="a" type="main" xml:lang="en">Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</title><author xml:id="author-1"><persName><forename type="first">Lydie</forename><surname>Ngandu</surname></persName><affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</affiliation></author><author xml:id="author-2"><persName><forename type="first">Dominique</forename><surname>Robin</surname></persName><affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</affiliation></author><author xml:id="author-3"><persName><forename type="first">Asma</forename><surname>El Kasmi</surname></persName><affiliation>School of Science and Engineering, Al Akhawayn University, PO Box 104, A. Hassan II, Ifrane 53000, Morocco</affiliation></author><author xml:id="author-4"><persName><forename type="first">Doris</forename><surname>Lexa</surname></persName><note type="correspondence"><p>Corresponding author. Tel.: +33-4-9116 4404; fax: +33-4-9116 4578</p></note><affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</affiliation></author></analytic><monogr><title level="j">Inorganica Chimica Acta</title><title level="j" type="abbrev">ICA</title><idno type="pISSN">0020-1693</idno><idno type="PII">S0020-1693(00)X0093-X</idno><imprint><publisher>ELSEVIER</publisher><date type="published" when="1999"></date><biblScope unit="volume">292</biblScope><biblScope unit="issue">2</biblScope><biblScope unit="page" from="204">204</biblScope><biblScope unit="page" to="212">212</biblScope></imprint></monogr><idno type="istex">C6DA6EA095A3203E58EC06107FF215D9BF99D781</idno><idno type="DOI">10.1016/S0020-1693(99)00193-0</idno><idno type="PII">S0020-1693(99)00193-0</idno></biblStruct></sourceDesc></fileDesc><profileDesc><creation><date>1999</date></creation><langUsage><language ident="en">en</language></langUsage><abstract xml:lang="en"><p>Several vitamin B12 derivatives (aquo, acetato, and glutathionyl cobalamins) adsorbed on an edge pyrolytic graphite electrode are studied in order to determine how their electrochemical behaviors are influenced by either the direct adsorption on the electrode material, or the adsorption in the presence of transport proteins, intrinsic factor (IF) and non-intrinsic factor (NIF). Comparison with the interfacial electrochemistry of the cobinamide demonstrates that, at neutral pH, the benzimidazole (Bzm) moiety is still coordinated to the Co(III) and Co(II) oxidized states of the adsorbed cobalamins. On the other hand, adsorption on pyrolytic graphite electrodes is shown to accelerate the kinetics for the reduction Co(III)/Co(II) when strong coordination by glutathione is involved compared to the results obtained in solution. The transport protein–cobalamin complexes are still reducible on the electrode. The potentials are not really changed for the IF complex while Co(II) is slightly more difficult to reduce in the case of the NIF complex.</p></abstract><textClass xml:lang="en"><keywords scheme="keyword"><list><head>Keywords</head><item><term>Vitamin B12 derivatives</term></item><item><term>Cobalamins</term></item><item><term>Electrochemistry</term></item></list></keywords></textClass><textClass xml:lang="en"><keywords scheme="keyword"><list><head>Abbreviations</head><item><term>Cbl, cobalamin</term></item><item><term>B12a, Co(III)balamin</term></item><item><term>B12r, Co(II)balamin</term></item><item><term>B12s, Co(I)balamin</term></item><item><term>Cbi, cobinamide</term></item><item><term>Bzm, benzimidazole</term></item><item><term>GSH, reduced glutathione</term></item><item><term>IF, intrinsic factor</term></item><item><term>NIF, non-intrinsic factor</term></item><item><term>CV, cyclic voltammetry</term></item><item><term>EPG, edge plane pyrolytic graphite</term></item><item><term>GC, glassy carbon</term></item><item><term>BR, Britton–Robinson</term></item><item><term>SCE, saturated calomel electrode</term></item></list></keywords></textClass></profileDesc><revisionDesc><change when="1999">Published</change></revisionDesc></teiHeader></istex:fulltextTEI><json:item><original>false</original><mimetype>text/plain</mimetype><extension>txt</extension><uri>https://api.istex.fr/document/C6DA6EA095A3203E58EC06107FF215D9BF99D781/fulltext/txt</uri></json:item></fulltext><metadata><istex:metadataXml wicri:clean="Elsevier, elements deleted: ce:floats; body; tail"><istex:xmlDeclaration>version="1.0" encoding="utf-8"</istex:xmlDeclaration><istex:docType PUBLIC="-//ES//DTD journal article DTD version 4.5.2//EN//XML" URI="art452.dtd" name="istex:docType"><istex:entity SYSTEM="gr1" NDATA="IMAGE" name="gr1"></istex:entity><istex:entity SYSTEM="gr2" NDATA="IMAGE" name="gr2"></istex:entity><istex:entity SYSTEM="gr3" NDATA="IMAGE" name="gr3"></istex:entity><istex:entity SYSTEM="sc1" NDATA="IMAGE" name="sc1"></istex:entity><istex:entity SYSTEM="sc2" NDATA="IMAGE" name="sc2"></istex:entity><istex:entity SYSTEM="sc3" NDATA="IMAGE" name="sc3"></istex:entity><istex:entity SYSTEM="gr4" NDATA="IMAGE" name="gr4"></istex:entity><istex:entity SYSTEM="gr5" NDATA="IMAGE" name="gr5"></istex:entity><istex:entity SYSTEM="gr6" NDATA="IMAGE" name="gr6"></istex:entity><istex:entity SYSTEM="fx1" NDATA="IMAGE" name="fx1"></istex:entity><istex:entity SYSTEM="gr7" NDATA="IMAGE" name="gr7"></istex:entity></istex:docType><istex:document><converted-article version="4.5.2" docsubtype="fla" xml:lang="en"><item-info><jid>ICA</jid><aid>7002</aid><ce:pii>S0020-1693(99)00193-0</ce:pii><ce:doi>10.1016/S0020-1693(99)00193-0</ce:doi><ce:copyright type="full-transfer" year="1999">Elsevier Science S.A.</ce:copyright></item-info><head><ce:title>Vitamin B<ce:inf>12</ce:inf>–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</ce:title><ce:author-group><ce:author><ce:given-name>Lydie</ce:given-name><ce:surname>Ngandu</ce:surname><ce:cross-ref refid="AFF1"><ce:sup>a</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Dominique</ce:given-name><ce:surname>Robin</ce:surname><ce:cross-ref refid="AFF1"><ce:sup>a</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Asma</ce:given-name><ce:surname>El Kasmi</ce:surname><ce:cross-ref refid="AFF2"><ce:sup>b</ce:sup></ce:cross-ref></ce:author><ce:author><ce:given-name>Doris</ce:given-name><ce:surname>Lexa</ce:surname><ce:cross-ref refid="AFF1"><ce:sup>a</ce:sup></ce:cross-ref><ce:cross-ref refid="CORR1">*</ce:cross-ref></ce:author><ce:affiliation id="AFF1"><ce:label>a</ce:label><ce:textfn>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</ce:textfn></ce:affiliation><ce:affiliation id="AFF2"><ce:label>b</ce:label><ce:textfn>School of Science and Engineering, Al Akhawayn University, PO Box 104, A. Hassan II, Ifrane 53000, Morocco</ce:textfn></ce:affiliation><ce:correspondence id="CORR1"><ce:label>*</ce:label><ce:text>Corresponding author. Tel.: +33-4-9116 4404; fax: +33-4-9116 4578</ce:text></ce:correspondence></ce:author-group><ce:date-received day="21" month="1" year="1999"></ce:date-received><ce:date-accepted day="16" month="4" year="1999"></ce:date-accepted><ce:abstract><ce:section-title>Abstract</ce:section-title><ce:abstract-sec><ce:simple-para>Several vitamin B<ce:inf>12</ce:inf> derivatives (aquo, acetato, and glutathionyl cobalamins) adsorbed on an edge pyrolytic graphite electrode are studied in order to determine how their electrochemical behaviors are influenced by either the direct adsorption on the electrode material, or the adsorption in the presence of transport proteins, intrinsic factor (IF) and non-intrinsic factor (NIF). Comparison with the interfacial electrochemistry of the cobinamide demonstrates that, at neutral pH, the benzimidazole (Bzm) moiety is still coordinated to the Co(III) and Co(II) oxidized states of the adsorbed cobalamins. On the other hand, adsorption on pyrolytic graphite electrodes is shown to accelerate the kinetics for the reduction Co(III)/Co(II) when strong coordination by glutathione is involved compared to the results obtained in solution. The transport protein–cobalamin complexes are still reducible on the electrode. The potentials are not really changed for the IF complex while Co(II) is slightly more difficult to reduce in the case of the NIF complex.</ce:simple-para></ce:abstract-sec></ce:abstract><ce:keywords class="keyword"><ce:section-title>Keywords</ce:section-title><ce:keyword><ce:text>Vitamin B<ce:inf>12</ce:inf> derivatives</ce:text></ce:keyword><ce:keyword><ce:text>Cobalamins</ce:text></ce:keyword><ce:keyword><ce:text>Electrochemistry</ce:text></ce:keyword></ce:keywords><ce:keywords class="abr"><ce:section-title>Abbreviations</ce:section-title><ce:keyword><ce:text>Cbl, cobalamin</ce:text></ce:keyword><ce:keyword><ce:text>B<ce:inf>12</ce:inf>a, Co(III)balamin</ce:text></ce:keyword><ce:keyword><ce:text>B<ce:inf>12</ce:inf>r, Co(II)balamin</ce:text></ce:keyword><ce:keyword><ce:text>B<ce:inf>12</ce:inf>s, Co(I)balamin</ce:text></ce:keyword><ce:keyword><ce:text>Cbi, cobinamide</ce:text></ce:keyword><ce:keyword><ce:text>Bzm, benzimidazole</ce:text></ce:keyword><ce:keyword><ce:text>GSH, reduced glutathione</ce:text></ce:keyword><ce:keyword><ce:text>IF, intrinsic factor</ce:text></ce:keyword><ce:keyword><ce:text>NIF, non-intrinsic factor</ce:text></ce:keyword><ce:keyword><ce:text>CV, cyclic voltammetry</ce:text></ce:keyword><ce:keyword><ce:text>EPG, edge plane pyrolytic graphite</ce:text></ce:keyword><ce:keyword><ce:text>GC, glassy carbon</ce:text></ce:keyword><ce:keyword><ce:text>BR, Britton–Robinson</ce:text></ce:keyword><ce:keyword><ce:text>SCE, saturated calomel electrode</ce:text></ce:keyword></ce:keywords></head></converted-article></istex:document></istex:metadataXml><mods version="3.6"><titleInfo lang="en"><title>Vitamin B12–transport protein interaction: electrochemistry of aquo- and glutathionyl-cobalamins adsorbed on carbon electrodes; role of the nucleotide chain</title></titleInfo><titleInfo type="alternative" lang="en" contentType="CDATA"><title>Vitamin B</title></titleInfo><name type="personal"><namePart type="given">Lydie</namePart><namePart type="family">Ngandu</namePart><affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Dominique</namePart><namePart type="family">Robin</namePart><affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Asma</namePart><namePart type="family">El Kasmi</namePart><affiliation>School of Science and Engineering, Al Akhawayn University, PO Box 104, A. Hassan II, Ifrane 53000, Morocco</affiliation><role><roleTerm type="text">author</roleTerm></role></name><name type="personal"><namePart type="given">Doris</namePart><namePart type="family">Lexa</namePart><affiliation>Laboratoire de Bioénergétique et d’Ingéniérie des Protéines, UPR CNRS 9036, 31 Chemin J. Aiguier, 13402 Marseille Cedex 20, France</affiliation><description>Corresponding author. Tel.: +33-4-9116 4404; fax: +33-4-9116 4578</description><role><roleTerm type="text">author</roleTerm></role></name><typeOfResource>text</typeOfResource><genre type="research-article" displayLabel="Full-length article"></genre><originInfo><publisher>ELSEVIER</publisher><dateIssued encoding="w3cdtf">1999</dateIssued><copyrightDate encoding="w3cdtf">1999</copyrightDate></originInfo><language><languageTerm type="code" authority="iso639-2b">eng</languageTerm><languageTerm type="code" authority="rfc3066">en</languageTerm></language><physicalDescription><internetMediaType>text/html</internetMediaType></physicalDescription><abstract lang="en">Several vitamin B12 derivatives (aquo, acetato, and glutathionyl cobalamins) adsorbed on an edge pyrolytic graphite electrode are studied in order to determine how their electrochemical behaviors are influenced by either the direct adsorption on the electrode material, or the adsorption in the presence of transport proteins, intrinsic factor (IF) and non-intrinsic factor (NIF). Comparison with the interfacial electrochemistry of the cobinamide demonstrates that, at neutral pH, the benzimidazole (Bzm) moiety is still coordinated to the Co(III) and Co(II) oxidized states of the adsorbed cobalamins. On the other hand, adsorption on pyrolytic graphite electrodes is shown to accelerate the kinetics for the reduction Co(III)/Co(II) when strong coordination by glutathione is involved compared to the results obtained in solution. The transport protein–cobalamin complexes are still reducible on the electrode. The potentials are not really changed for the IF complex while Co(II) is slightly more difficult to reduce in the case of the NIF complex.</abstract><note type="content">Fig. 1: (A) Structures of vitamin B12 derivatives in the base-on form (L=H2O, OH−, glutathionyl, acetato). (B) Diaquocobinamide, (L=H2O).</note><note type="content">Fig. 2: CV in pH 5.06 BR buffer on coated pyrolytic graphite electrode. (A) First scan, starting potential +0.6 to −1.1 V; v=200 mV s−1; 20°C; solid line, hydroxoCbl; dashed line, acetatoCbl. (B) Variation of the reduction waves of acetatoCbl adsorbed on pyrolytic graphite electrode with the pH in BR buffer; v=200 mV s−1, 20°C. Second and others scans at solid line, pH 2, dotted line, pH 5, dashed line, pH 9.</note><note type="content">Fig. 3: CV in pH 5.06 BR buffer of (A) acetatoCbl adsorbed on pyrolytic graphite electrode; variations with the sweep rate: v=50, 150, 200 mV s−1. (B) DiaquoCbi adsorbed on pyrolytic graphite electrode at the same pH. Starting potential: −0.3 V; variation with the sweep rate, v=50, 100, 200 mV s−1.</note><note type="content">Scheme 1: </note><note type="content">Scheme 2: </note><note type="content">Scheme 3: </note><note type="content">Fig. 4: CV in a solution pH 6.36 of BR buffer, on a glassy carbon electrode; v=200 mV s−1; titration with glutathione: (A) solid line, aquoCbl (c=2.3×10−3 M l−1); dashed line, +GSH (c=1.6× 10−3 M l−1); dotted line, +GSH (c=2.3×10−3 M l−1). (B) GSHCbl in the same solution: variation with the sweep rate: dotted line, v=20; dashed line, v=50; solid line, v=100 mV s−1.</note><note type="content">Fig. 5: CV of aquocobalamin adsorbed on EPG in pH 5.7 BR buffer, v=100 mV s−1: (A) solid line, aquobalamin; dashed line, +10−2 M l−1 glutathione; (B) after several scans: solid line, starting +0.5 to −1 V; dashed line, starting −0.9 to +0.5 V.</note><note type="content">Fig. 6: Optical study of the complexation of B12r prepared by preparative electrolysis in pH 5.7 BR buffer; optical path cell, 0.2 cm. (a) Solid line, spectrum of B12r (c=2.96×10−4 M l−1), (b) dashed line, spectrum evolution after the adduct of glutathione (3×10−1 M l−1).</note><note type="content">Fig. 7: CV of acetatocobalamin on EPG in pH 7 BR buffer, v=200 mV s−1: solid line, acetatoCbl (1×10−12 mol mm−2 deposited); dotted line, IF+acetatoCbl (0.2 units+1.5×10−12 mol mm−2 deposited).</note><note type="content">Table 1: </note><note type="content">Table 2: Formal potentials of aquo- and glutathionyl-cobalamin at pH 5.7</note><subject lang="en"><genre>Keywords</genre><topic>Vitamin B12 derivatives</topic><topic>Cobalamins</topic><topic>Electrochemistry</topic></subject><subject lang="en"><genre>Abbreviations</genre><topic>Cbl, cobalamin</topic><topic>B12a, Co(III)balamin</topic><topic>B12r, Co(II)balamin</topic><topic>B12s, Co(I)balamin</topic><topic>Cbi, cobinamide</topic><topic>Bzm, benzimidazole</topic><topic>GSH, reduced glutathione</topic><topic>IF, intrinsic factor</topic><topic>NIF, non-intrinsic factor</topic><topic>CV, cyclic voltammetry</topic><topic>EPG, edge plane pyrolytic graphite</topic><topic>GC, glassy carbon</topic><topic>BR, Britton–Robinson</topic><topic>SCE, saturated calomel electrode</topic></subject><relatedItem type="host"><titleInfo><title>Inorganica Chimica Acta</title></titleInfo><titleInfo type="abbreviated"><title>ICA</title></titleInfo><genre type="journal">journal</genre><originInfo><dateIssued encoding="w3cdtf">19990915</dateIssued></originInfo><identifier type="ISSN">0020-1693</identifier><identifier type="PII">S0020-1693(00)X0093-X</identifier><part><date>19990915</date><detail type="volume"><number>292</number><caption>vol.</caption></detail><detail type="issue"><number>2</number><caption>no.</caption></detail><extent unit="issue pages"><start>149</start><end>282</end></extent><extent unit="pages"><start>204</start><end>212</end></extent></part></relatedItem><identifier type="istex">C6DA6EA095A3203E58EC06107FF215D9BF99D781</identifier><identifier type="DOI">10.1016/S0020-1693(99)00193-0</identifier><identifier type="PII">S0020-1693(99)00193-0</identifier><accessCondition type="use and reproduction" contentType="copyright">©1999 Elsevier Science S.A.</accessCondition><recordInfo><recordContentSource>ELSEVIER</recordContentSource><recordOrigin>Elsevier Science S.A., ©1999</recordOrigin></recordInfo></mods></metadata><serie></serie></istex></record>Pour manipuler ce document sous Unix (Dilib)
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