| Name | Peptidase family T3 (gamma-glutamyltransferase family) |
|---|
| Family type peptidase | T03.001 - gamma-glutamyltransferase 1 (bacterial-type) (Escherichia coli), MEROPS Accession MER0001978 (peptidase unit: 26-580) |
| Content of family | Peptidase family T3 contains self-processing proteins that express aminopeptidase as well as aminotransferase activities in their mature forms. |
| History |
Identifier created: MEROPS 3.1 (22 December 1998)
gamma-Glutamyltransferase, the most fully characterised peptidase in family T3, has been reviewed by Hiratake et al. (2004). |
| Catalytic type | Threonine |
| Active site residues | T,S391 |
| Active site | In bacterial gamma-glutamyltransferase, Thr391 (see the Alignment) is believed to be the key catalytic residue in both the maturation of the precursor and the transglutaminase reaction (Suzuki & Kumagai, 2002). Some processing occurred in a Thr391Ser mutant. The corresponding Thr residue is probably responsible for both reactions in the mammalian enzyme also, but for this the data are less clear. |
| Activities and specificities | The precursor of gamma-glutamyltransferase (T03.001) from Escherichia coli undergoes an autolytic cleavage on the amino side of Thr391 (see the Alignment) (Suzuki & Kumagai, 2002). Mature gamma-glutamyltranferase (T03.001) catalyzes the transfer of the gamma-glutamyl moiety of gamma-glutamyl-derived peptides such as glutathione (gammaGlu-Cys-Gly), and anilides such as gamma-glutamyl-7-amido-4-methylcoumarin (gammaGlu-AMC) to acceptor molecules including water and various dipeptides (Stein et al., 2001). The only other family of peptidases in which autolytic cleavage is known to give rise to peptidases acting on other substrates is T1, also in clan PB. |
| Inhibitors | Gamma-glutamyltrasferase is inhibited by 6-diazo-5-oxo-L-norleucine and L-azaserine (Tate & Meister, 1977) as well as the serine-borate complex (Tate & Meister, 1978). The compound acivicin (L-(alpha S,5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazole acetic acid) is also effective (Stole et al., 1994; Smith et al., 1995), and the enzyme is potently inhibited by the gamma-boronic acid analogue of L-glutamic acid, 3-amino-3-carboxypropaneboronic acid (gamma-boroGlu) (Stein et al., 2001). |
| Molecular structure | A preliminary description of the structure of Escherichia coli gamma-glutamyltranferase published by Sakai et al. (1996), shows a fold similar to that of an N-terminal nucleophile hydrolase (Brannigan et al., 1995; Suzuki & Kumagai, 2002). For this reason, family T3 is placed in clan PB. The single-chain precursor becomes a heterodimer on self-cleavage (Hashimoto et al., 1995). |
| Clan | PB |
| Subclan | PB(T) |
| Basis of clan assignment | The active site residue for members of this family and family T1 is C-terminal to the autolytic cleavage site. |
| Peptidases and Homologues |
MEROPS ID |
Structure |
| gamma-glutamyltransferase 1 (bacterial-type) | T03.001 | Yes |
| gamma-glutamyltransferase 5 (mammalian-type) | T03.002 | - |
| gamma-glutamyltransferase CG17636 (Diptera) | T03.005 | - |
| gamma-glutamyltransferase 1 (mammalian-type) | T03.006 | Yes |
| gamma-glutamyltransferase (insect) | T03.007 | - |
| gamma-glutamyltransferase (plant) | T03.008 | - |
| gamma-glutamyltransferase (nematode ) | T03.009 | - |
| gamma-glutamyltransferase CG1492 (Drosophila-type) | T03.010 | - |
| gamma-glutamyltransferase (Schizosaccharomyces-type) | T03.011 | - |
| gamma-glutamyltransferase (Saccharomyces-type) | T03.012 | - |
| gamma-glutamyltransferase (Synechocystis-type) | T03.013 | - |
| gamma-glutamyltransferase 2 (bacterial) | T03.014 | - |
| gamma-glutamyltransferase 2 (Homo sapiens) | T03.015 | - |
| gamma-glutamyltransferase-like protein 4 | T03.016 | - |
| gamma-glutamyltransferase-like protein 3 | T03.017 | - |
| protein similar to gamma-glutamyltransferase 1 precursor | T03.018 | - |
| similar to gamma-glutamyltransferase 1 precursor (Homo sapiens) | T03.019 | - |
| Mername-AA211 putative peptidase | T03.021 | - |
| 9030405D14Rik putative peptidase | T03.022 | - |
| CapD poly-gamma-glutamate hydrolase | T03.023 | Yes |
| gamma-glutamyltransferase 6 | T03.024 | - |
| oxamate amidohydrolase proenzyme (Klebsiella pneumonia) | T03.025 | Yes |
| gamma-glutamyl transpeptidase homologue (chromosome 2, Homo sapiens) and similar | T03.971 | - |
| At4g29210 (Arabidopsis thaliana) | T03.A01 | - |
| At4g39650 (Arabidopsis thaliana) | T03.A03 | - |
| CG6461 protein (Drosophila melanogaster) | T03.A04 | - |
| C53D5.5 g.p. (Caenorhabditis elegans) | T03.A05 | - |
| H14N18.4a g.p. (Caenorhabditis elegans) | T03.A06 | - |
| Y7A9A.1 g.p. (Caenorhabditis elegans) | T03.A07 | - |
| T19H12.6 g.p. (Caenorhabditis elegans) | T03.A08 | - |
| Family T03 non-peptidase homologues | non-peptidase homologue | - |
| Family T03 unassigned peptidases | unassigned | - |
