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Studies on the Reduction of Dehydroascorbic Acid by Glutathione in the Presence of Aquahydroxocobinamide
Author(s) -
Dereven'kov Ilia A.,
Makarov Sergei V.,
Bui Thi Thu Thuy,
Makarova Anna S.,
Koifman Oskar I.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800066
Subject(s) - dehydroascorbic acid , chemistry , glutathione , ascorbic acid , vitamin c , catalysis , redox , stereochemistry , biochemistry , organic chemistry , enzyme , food science
This study reports that aquahydroxocobinamide [(H 2 O)(HO – )Cbi(III)], a nucleotide‐free analogue of cobalamin (vitamin B 12 ; Cbl), is capable of catalyzing the reduction of the two‐electron oxidized form of vitamin C, dehydroascorbic acid (DHA), to ascorbic acid by glutathione (GSH), whereas catalytic quantities of aquacobalamin do not accelerate the reaction. This observation is explained by different reactions taking place with the Co III ‐species of these complexes and GSH: Cbl(III) forms a stable complex with GSH, but Cbi(III) is relatively rapidly reduced to Cbi(II). The reaction of Cbi(II) with DHA in the presence of GSH includes the coordination of GSH onto Co II , the reaction of GS – –Cbi(II) with DHA produces GS – –Cbi(III) and the ascorbyl radical, which rapidly disproportionates to a mixture of ascorbic and dehydroascorbic acids, and further regeneration of Cbi(II).