HGNC Approved Gene Symbol: GGTLC3
Cytogenetic location: 22q11.21 Genomic coordinates (GRCh38): 22:18,516,338-18,518,166 (from NCBI)
Gamma-glutamyltransferase-1 (GGT1; 612346) is a membrane-bound extracellular enzyme that cleaves gamma-glutamyl peptide bonds in glutathione and other peptides and transfers the gamma-glutamyl moiety to acceptors. Autocatalytic cleavage of the GGT1 precursor polypeptide produces a heavy chain and a light chain that associate with each other to form the functional enzyme. Light chain-only GGTs, such as GGTLC3, contain a region corresponding to the GGT1 light chain, but they lack the membrane-anchoring heavy chain region (Heisterkamp et al., 2008).
Courtay et al. (1994) obtained partial genomic sequences of several GGT genes and pseudogenes, including GGTLC3, which they designated clone 11.
Heisterkamp et al. (2008) noted that the glutamate-binding site of GGT1 includes 8 residues in its light chain and 1 residue (arg107) in its heavy chain. They determined that GGTLC3, which encodes a protein corresponding to the GGT1 light chain only, contains residues corresponding to 7 of the 8 glutamate-binding residues in the GGT1 light chain, but it lacks a residue equivalent to arg107 in the GGT1 heavy chain.
By genomic sequence analysis, Heisterkamp et al. (2008) mapped the GGTLC3 gene to chromosome 22q11.2.
Courtay, C., Heisterkamp, N., Siest, G., Groffen, J. Expression of multiple gamma-glutamyltransferase genes in man. Biochem. J. 297: 503-508, 1994. [PubMed: 7906515] [Full Text: https://doi.org/10.1042/bj2970503]
Heisterkamp, N., Groffen, J., Warburton, D., Sneddon, T. P. The human gamma-glutamyltransferase gene family. Hum. Genet. 123: 321-332, 2008. [PubMed: 18357469] [Full Text: https://doi.org/10.1007/s00439-008-0487-7]