Thiol dependent isomerization of bovine albumin.
Albumin isomerizes to the aged form in the presence of cysteine at pH 8.9 and low ionic strength. Albumins with a high fatty acid and Cu(II) content do not produce isomers, and recover this capacity after an acid expansion. Isomers have the free thiol group fully oxidized (non-mercaptalbumin) and have been isolated for the first time from aged albumins by anion and cation exchange chromatography. Isomers have a higher susceptibility to limited tryptic digestion and show a decrease in the fluorescence of bound dansylamide, a typical marker of site I. Aging in the presence of phenylarsine oxide, which complexes vicinal thiols, impairs the formation of isomers and increases the free -SH groups of albumin.
Gabaldon
María
M
Centro de Investigación, Hospital La Fe, Avenida Campanar 21, 46009 Valencia, Spain. maria.gabaldon@ono.com
D001152:Arsenicals; D002852:Chromatography, Ion Exchange; D003619:Dansyl Compounds; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000032:analysis; D005453:Fluorescence; D007536:Isomerism; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000302:isolation & purification; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D001152:Arsenicals; D003619:Dansyl Compounds; D005227:Fatty Acids; D013438:Sulfhydryl Compounds; C029341:oxophenylarsine; C001026:5-dimethylaminonaphthalene-1-sulfonamide; D012710:Serum Albumin, Bovine