putative catalytic domain of glycoside hydrolase family 119 (GH119)
The prokaryotic subgroup is represented by IgtZ, an alpha-amylase from a Bacillus circulans strain. The GH119 family is related to GH57, a chiefly prokaryotic family with the majority of thermostable enzymes coming from extremophiles (many of these are archaeal hyperthermophiles), which exhibit the enzyme specificities of alpha-amylase (EC 3.2.1.1), 4-alpha-glucanotransferase (EC 2.4.1.25), amylopullulanase (EC 3.2.1.1/41), and alpha-galactosidase (EC 3.2.1.22). GH57s cleave alpha-glycosidic bonds by employing a retaining mechanism, which involves a glycosyl-enzyme intermediate, allowing transglycosylation.
Jiyao W et al.(2023). "The conserved domain database in 2023.",