S-Nitrosoglutathione covalently modifies cysteine residues of human carbonyl reductase 1 and affects its activity
Abstract
Carbonyl reductase 1 (CBR1 or SDR21C1) is a ubiquitously-expressed, cytosolic, monomeric, and NADPH-dependent enzyme. CBR1 participates in apoptosis, carcinogenesis and drug resistance, and has a protective role in oxidative stress, cancer and neurodegeneration.
S-Nitrosoglutathione (GSNO) represents the newest addition to its diverse substrate spectrum, which includes a wide range of xenobiotics and endogenous substances. GSNO has also been shown to covalently modify and inhibit CBR1.
The aim of the present study was to quantify and characterize the resulting modifications. The findings indicate that GSNO-induced covalent modification of cysteine residues affects the kinetic mechanism of CBR1 both in terms of substrate binding and turnover rate, probably by covalent modification of Cys-226 and/or Cys-227.