Class I triad glutamine amidotransferase (Class I GATase)

Class I triad glutamine amidotransferases (GATases), also known as G-type amidotransferases, are enzymes that facilitate the transfer of an amide nitrogen from glutamine to various substrates, a process essential for the biosynthesis of nucleotides, amino acids, and amino sugars (Massière & Badet-Denisot, 1998). These enzymes are defined by a conserved catalytic triad—typically Cysteine, Histidine, and Glutamate—where the cysteine acts as a nucleophile to form a glutamyl-enzyme intermediate (Zalkin & Smith, 1998). Because they are central to the production of DNA and RNA precursors, they are vital for the growth of rapidly dividing cells, making them attractive targets for anticancer and antimicrobial therapies (Chittur et al., 2001). Historically, glutamine analogs like acivicin have been used to inhibit these enzymes by covalently modifying the active-site cysteine, though their clinical utility has been limited by significant toxicity due to the broad inhibition of multiple glutamine-dependent pathways (Mouilleron & Golinelli-Pimpaneau, 2007). Modern research focuses on developing more selective inhibitors to mitigate these safety concerns while exploiting the metabolic dependencies of specific diseases.

Other names

G-type glutamine amidotransferaseTriad glutamine amidotransferaseGlutamine amidotransferase class I

Irreversible inhibition of the glutamine-binding site via covalent modification of the catalytic cysteine residue.