Serine hydrolase
Serine hydrolases are one of the largest known enzyme classes comprising approximately ~200 enzymes or 1% of the genes in the human proteome.[1] A defining characteristic of these enzymes is the presence of a nucleophilic serine in their active site, which is used for the hydrolysis of substrates. Catalysis proceeds by the formation of an acyl-enzyme intermediate through this serine, followed by water/hydroxide-induced saponification of the intermediate and regeneration of the enzyme. Unlike other non-catalytic serines, the nucleophilic serine of these hydrolases is typically activated by a proton relay involving a catalytic triad consisting of the serine, an acidic residue (e.g. aspartate or glutamate) and a basic residue (usually histidine), although variations on this mechanism exist.
Superfamilies of serine hydrolases includes:
- Serine proteases, including trypsin, chymotrypsin, and subtilisin
- Extracellular lipases, including pancreatic lipase, hepatic lipase, gastric lipase, endothelial lipase, and lipoprotein lipase
- Intracellular lipases, including hormone sensitive lipase, monoacylglycerol lipase, adipose triglyceride lipase, and diacylglycerol lipase
- Cholinesterases, including acetylcholinesterase and butyrylcholinesterase
- Small molecule thioesterases, including fatty acid synthase and the acyl-CoA thioesterases
- Some phospholipases, including phospholipase A2 and platelet activating factor acetylhydrolase
- Protein and glycan hydrolases, including protein phosphate methylesterase 1, acyloxyacyl hydrolase and sialic acid acetylesterase
- Some amidases, including fatty acid amide hydrolase
- Some peptidases, including dipeptidyl peptidase 4, fibroblast activation protein, and prolylendopeptidase
See also
References
- ↑ Simon GM, Cravatt BF (April 2010). "Activity-based proteomics of enzyme superfamilies: serine hydrolases as a case study". J. Biol. Chem. 285 (15): 11051–5. doi:10.1074/jbc.R109.097600. PMC 2856978
. PMID 20147750.