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Kinetic and Mechanistic Studies on the Reaction between Aquacobalamin and Selenocysteine
Author(s) -
Dereven'kov Ilia A.,
Polyakova Anastasiya Yu.,
Makarov Sergei V.
Publication year - 2017
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.201700973
Subject(s) - chemistry , selenocysteine , cysteine , selenium , stereochemistry , coordination complex , reaction mechanism , spectroscopy , medicinal chemistry , catalysis , enzyme , organic chemistry , metal , physics , quantum mechanics
We studied the reaction between aquacobalamin (H 2 OCbl) and selenocysteine (Sec), a selenium‐containing analogue of cysteine, using conventional UV/Vis spectroscopy. This reaction leads to the formation of cob(II)alamin [Cbl(II)] without any detectable intermediate complexation of Cbl(III) with selenocysteine, whereas the interaction between H 2 OCbl and cysteine proceeds distinctly through the coordination of Cys onto the Co III ion with further reduction of the Co III –Cys complex to Cbl(II). The latter is slower than the reaction with Sec. We also showed that selenocystine is capable of accelerating the reduction of H 2 OCbl to Cbl(II) by cysteine.