Type 1 glutamine amidotransferase (GATase1)-like domain found in peptidase E
Type 1 glutamine amidotransferase (GATase1)-like domain found in peptidase E. This group contains proteins similar to the aspartyl dipeptidases Salmonella typhimurium peptidase E and Xenopus laevis peptidase E. In bacteria peptidase E is believed to play a role in degrading peptides generated by intracellular protein breakdown or imported into the cell as nutrient sources. Peptidase E uniquely hydrolyses only Asp-X dipeptides (where X is any amino acid), and one tripeptide Asp-Gly-Gly. Peptidase E is believed to be a serine peptidase having a Ser-His-Glu catalytic triad which differs from the Cys-His-Glu catalytic triad typical of GATase1 domains by having a Ser in place of the reactive Cys at the nucleophile elbow. Xenopus PepE is developmentally regulated in response to thyroid hormone and, it is thought to play a role in apoptosis during tail reabsorption.