PROSITE documentation PDOC00903

Lipolytic enzymes "G-D-X-G" family, putative active sites signatures

The following lipolytic enzymes are evolutionary related [1]:

• Mammalian hormone sensitive lipase (HSL). In adipose tissue and heart, HSL primarily hydrolyzes stored triglycerides to free fatty acids, while in steroidogenic tissues, it principally converts cholesteryl esters to free cholesterol for steroid hormone production.
• Mammalian arylacetamide deacetylase (DAC).
• Moraxella strain TA144 lipase 2 (gene lip2), an enzyme active at a low temperature.
• Acinetobacter calcoaceticus esterase which seems to be active on simple triglycerides such as triacetin.
• Streptomyces hygroscopicus acetyl-hydrolase (gene bah), which removes the N-acetyl group from the antibiotic bialaphos.
• Escherichia coli acetyl esterase aes.

In Moraxella lip2, the mutagenesis [2] of either an histidine or a serine results in the loss of the activity of the enzyme. These putative active site residues are each centered in conserved regions that can be used as signature patterns.