Autocatalytic cleavage of human gamma-glutamyl transpeptidase is highly dependent on N-glycosylation at asparagine 95.

ABSTRACT: γ-Glutamyl transpeptidase (GGT) is a heterodimeric membrane enzyme that catalyzes the cleavage of extracellular glutathione and other γ-glutamyl-containing compounds. GGT is synthesized as a single polypeptide (propeptide) that undergoes autocatalytic cleavage, which results in the formation of the large and small subunits that compose the mature enzyme. GGT is extensively N-glycosylated, yet the functional consequences of this modification are unclear. We investigated the effect of N-glycosylation on the kinetic behavior, stability, and functional maturation of GGT. Using site-directed mutagenesis, we confirmed that all seven N-glycosylation sites on human GGT are modified by N-glycans. Comparative enzyme kinetic analyses revealed that single substitutions are functionally tolerated, alth

SUBMITTER: West MB 

PROVIDER: S-EPMC3190695 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature