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Analysis of Conserved Region of Glutathione Synthetase
Author(s) -
Castano Jaclyn A.,
Brown Teresa,
Koo Julie,
Bhansali Vikas S.,
Anderson Mary E
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a475
Subject(s) - glutathione synthetase , glutathione , chemistry , genetics , biochemistry , biology , enzyme
Glutathione (GSH; γ‐glutamylcysteinglycine) is an important antioxidant present in most living organisms. GSH is synthesized in two enzymatic steps. Glutathione synthetase (GS) catalyzes the second reaction, joining of γ‐glutamylcysteine with glycine in an ATP‐dependent reaction. Human GS is a homodimer, and each subunit is composed of 474 amino acids. Our recent bioinformatics studies have shown a conserved loop in mammals near the substrate, called the Sloop. This loop has been suggested to be involved in γ‐glutamylcysteine binding. There are known patient mutations in this region, Tyr270 to Cys and also to His, that lead to decreased enzyme activity. We prepared human GS mutant enzymes at Y270 and other residues in region using site‐directed mutagenesis. Our preliminary findings show that these mutations lead to decreased activity of human GS, as compared to wild type. Our studies will provide insight into this important enzyme of GSH synthesis. (This research is supported in part by a new Faculty Research Enhancement Grant (MEA) and a grant from the Welch Foundation to the Department of Chemistry at TWU.)