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Titolo:
ELECTROCHEMICAL REDUCTION OF THE BILIVERDIN-SERUM ALBUMIN COMPLEX AS MONITORED BY ABSORPTION AND CIRCULAR-DICHROISM SPECTROSCOPY
Autore:
CLARET J; IBARS O; LANG K; TRULL FR; LIGHTNER DA;
Indirizzi:
UNIV BARCELONA,FAC QUIM,DEPT QUIM ORGAN,C-MARTI & FRANQUES 1 E-08028 BARCELONA SPAIN UNIV BARCELONA,FAC QUIM,DEPT QUIM ORGAN E-08028 BARCELONA SPAIN UNIV BARCELONA,FAC QUIM,DEPT QUIM FIS E-08028 BARCELONA SPAIN UNIV NEVADA,DEPT CHEM RENO NV 89557
Titolo Testata:
Biochimica et biophysica acta (G). General subjects
fascicolo: 2, volume: 1243, anno: 1995,
pagine: 221 - 229
SICI:
0304-4165(1995)1243:2<221:EROTBA>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
BILIRUBIN-IX-ALPHA; BILE-PIGMENTS; PYRROLE PIGMENTS; DIMETHYL FORMAMIDE; SUPEROXIDE ION; REACTIVITY; OXIDATION; 5(1H)-PYRROMETHENONES; CONFORMATION;
Keywords:
BILIRUBIN; BILIVERDIN; HUMAN SERUM ALBUMIN; BOVINE SERUM ALBUMIN; CIRCULAR DICHROISM; ALBUMIN BINDING; VOLTAMMETRIC REDUCTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
34
Recensione:
Indirizzi per estratti:
Citazione:
J. Claret et al., "ELECTROCHEMICAL REDUCTION OF THE BILIVERDIN-SERUM ALBUMIN COMPLEX AS MONITORED BY ABSORPTION AND CIRCULAR-DICHROISM SPECTROSCOPY", Biochimica et biophysica acta (G). General subjects, 1243(2), 1995, pp. 221-229

Abstract

The cathodic reduction at the mercury electrode of a biliverdin IX alpha-serum albumin complex at physiological pH in an aqueous buffer containing percentages of DMSO ranging from 4% to 20% is studied by cyclic voltametry and controlled potential coulometry. The progression of pigment disappearance and the (stereochemical) nature of the product are monitored by chromatography, UV-visible absorption and circular dichroism spectroscopy. Upon reduction, albumin-bound biliverdin IX alpha,with a slight preference for the P-helicity, affords the corresponding bound bilirubin IX alpha -with an M-chirality conformation. The complex is reduced at -0.64 V (vs. SCE; 8% DMSO), only a little shifted compared to reduction of free biliverdin IX alpha under the same conditions. In contrast, an analogous bilirubin IX alpha-serum albumin complex is essentially inert towards cathodic reduction under conditions where free bilirubin IX alpha is reduced, indicating a better shielding by the protein of the bilirubin IX alpha molecule from the electrode surface. The presence and relative position (as in the biliverdins IX alpha and XIII alpha) or absence (as in mesobiliverdin IX alpha) of vinyl groups in the pigment does not have a significant effect upon its electroreduction behaviour, indicating that the process is not sensitiveto the subtle differences imposed by vinyl groups upon the structure of the corresponding biliverdin-albumin complexes.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/07/20 alle ore 21:50:20