Inactivation of human S-adenosylhomocysteine hydrolase by covalent labeling of cysteine 195 with thionucleoside derivatives.
A new series of 5'-thioadenosine derivatives 1-4 were synthesized for selectively targeting (195)Cys of human AdoHcy hydrolase. Their incubation with the enzyme resulted in time- and concentration-dependent inactivation, without major modifications of the NAD(+)/NADH ratio. The electrospray mass analysis of the inactivated enzyme with 1, 2, 3, and 4b showed that inhibition was accompanied by the formation of a specific and covalent labeling of each AdoHcy hydrolase subunit. Proteolytic cleavage (endo-Lys-C) and subsequent peptide characterization of the labeled enzyme revealed that (195)Cys was the residue modified during the inactivation process.
Guillerm
Georges
G
Laboratoire de Chimie bioorganique, UMR 6519, UFR Sciences, B.P. 1039, 51687 Reims Cedex 2, France.
Muzard
Murielle
M
Glapski
Cédric
C
Pilard
Serge
S
D043383:Adenosylhomocysteinase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D011480:Protease Inhibitors / Q000737:chemistry* / Q000494:pharmacology; D013872:Thionucleosides / Q000737:chemistry* / Q000494:pharmacology
D011480:Protease Inhibitors; D013872:Thionucleosides; D043383:Adenosylhomocysteinase; D003545:Cysteine