S-Nitrosoglutathione as a substrate for gamma-glutamyl transpeptidase. Biochem J 1997 Apr 15;323 ( Pt 2)(Pt 2):477-81
Date
04/15/1997Pubmed ID
9163341Pubmed Central ID
PMC1218344DOI
10.1042/bj3230477Scopus ID
2-s2.0-0030945376 (requires institutional sign-in at Scopus site) 122 CitationsAbstract
S-Nitrosoglutathione (GSNO) has been used as a nitric oxide (.NO) donor compound and has also been postulated to be involved in the transport of .NO in vivo. In this study we have examined the possibility that GSNO is a substrate for gamma-glutamyl transpeptidase (gamma-GT), an enzyme that hydrolyses the gamma-glutamyl moiety of glutathione to give glutamate and cysteinylglycine. gamma-GT accelerated the decomposition of GSNO, forming S-nitrosocysteinylglycine (CG-SNO) by a mechanism inhibitable by the gamma-GT inhibitors acivicin and S-methylglutathione. The Km of gamma-GT for GSNO was found to be 28 microM. In the presence of contaminating transition metal ions, gamma-GT accelerated the release of ;NO from GSNO, as CG-SNO is more susceptible to transition metal ion-dependent decomposition than GSNO. However, in the presence of the transition metal ion chelator diethylenetriaminepentaacetic acid, neither GSNO nor CG-SNO decomposed to generate .NO. Neither S-methylglutathione nor acivicin affected the vasodilatory response to GSNO in an isolated perfused rat heart. However, rat kidney homogenate stimulated the decomposition of GSNO by an acivicin-inhibitable mechanism. It is likely therefore that gamma-GT is involved in the decomposition of GSNO in the kidney but not in the heart.
Author List
Hogg N, Singh RJ, Konorev E, Joseph J, Kalyanaraman BAuthors
Neil Hogg PhD Associate Dean, Professor in the Biophysics department at Medical College of WisconsinBalaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsCoronary Circulation
Electron Spin Resonance Spectroscopy
Glutathione
In Vitro Techniques
Kidney
Kinetics
Male
Nitroso Compounds
Platelet Aggregation Inhibitors
Rats
Rats, Sprague-Dawley
S-Nitrosoglutathione
Vasodilation
gamma-Glutamyltransferase