LMPD Database

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LMP001635

UniProt Annotations

Entry Information
Gene Namegamma-glutamyltransferase 1
Protein EntryGGT1_HUMAN
UniProt IDP19440
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative promoter usage, Alternative splicing; Named isoforms=3; Name=1; IsoId=P19440-1; Sequence=Displayed; Note=Produced by alternative promoter usage.; Name=2; IsoId=P19440-2; Sequence=VSP_001746, VSP_001747; Note=Produced by alternative splicing of isoform 1.; Name=3; IsoId=P19440-3; Sequence=VSP_008132; Note=Produced by alternative promoter usage.;
Catalytic ActivityA (5-L-glutamyl)-peptide + an amino acid = a peptide + a 5-L-glutamyl amino acid.
Catalytic ActivityGlutathione + H(2)O = L-cysteinylglycine + L- glutamate.
Catalytic ActivityLeukotriene C(4) + H(2)O = leukotriene D(4) + L-glutamate.
DiseaseGlutathionuria (GLUTH) [MIM
Enzyme RegulationActivated by autocatalytic cleavage.
FunctionCleaves the gamma-glutamyl bond of extracellular glutathione (gamma-Glu-Cys-Gly), glutathione conjugates, and other gamma-glutamyl compounds. The metabolism of glutathione releases free glutamate and the dipeptide, cysteinyl-glycine, which is hydrolyzed to cysteine and glycine by dipeptidases. In the presence of high concentrations of dipeptides and some amino acids, can also catalyze a transpeptidation reaction, transferring the gamma-glutamyl moiety to an acceptor amino acid to form a new gamma-glutamyl compound. Initiates extracellular glutathione (GSH) breakdown, provides cells with a local cysteine supply and contributes to maintain intracellular GSH level. It is part of the cell antioxidant defense mechanism. Isoform 3 seems to be inactive. {ECO
MiscellaneousChloride ions bound in the active site cavity may contribute to stabilize the protein fold.
MiscellaneousCys-454 was thought to bind the gamma-glutamyl moiety, but mutagenesis of this residue had no effect on activity.
PathwaySulfur metabolism; glutathione metabolism.
PtmCleaved by autocatalysis into a large and a small subunit and the autocatalytic cleavage is essential to the functional activation of the enzyme.
PtmN-glycosylated on both chains. Contains hexoses, hexosamines and sialic acid residues. Glycosylation profiles tested in kidney and liver tissues reveal the presence of tissue-specific and site- specific glycan composition, despite the overlap in composition among the N-glycans. A total of 36 glycan compositions, with 40 unique structures are observed. Up to 15 different glycans are observed at a single site, with site-specific variation in glycan composition. The difference in glycosylation profiles in the 2 tissues do not affect the enzyme activity. {ECO
Sequence CautionSequence=AAA35899.1; Type=Erroneous initiation; Note=Translation N-terminally shortened.; Evidence= ;
SimilarityBelongs to the gamma-glutamyltransferase family.
Subcellular LocationCell membrane {ECO
SubunitHeterodimer composed of the light and heavy chains. The active site is located in the light chain.
Tissue SpecificityDetected in fetal and adult kidney and liver, adult pancreas, stomach, intestine, placenta and lung. Isoform 3 is lung-specific. There are several other tissue-specific forms that arise from alternative promoter usage but that produce the same protein.
Web ResourceName=Wikipedia; Note=Gamma-glutamyl transpeptidase entry; URL="http://en.wikipedia.org/wiki/Gamma_glutamyl_transpeptidase";