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Gluzincin Peptidase family (thermolysin-like proteinases, TLPs) which includes peptidases M1, M2, M3, M4, M13, M32 and M36 (fungalysins) The Gluzincin family (thermolysin-like peptidases or TLPs) includes several zinc-dependent metallopeptidases such as M1, M2, M3, M4, M13, M32, M36 peptidases (MEROPS classification), which contain the HEXXH motif as part of their active site. Peptidases in this family bind a single catalytic zinc ion which is tetrahedrally co-ordinated by three amino acid ligands and a water molecule that forms the nucleophile on activation during catalysis. The M1 family includes aminopeptidase N (APN) and leukotriene A4 hydrolase (LTA4H). APN preferentially cleaves neutral amino acids from the N-terminus of oligopeptides and is present in a variety of human tissues and cell types. LTA4H is a bifunctional enzyme, possessing an aminopeptidase as well as an epoxide hydrolase activity such that the two activities occupy different, but overlapping sites. The M3_like peptidases include the M2_ACE, M3 or neurolysin-like family (subfamilies M3B_PepF and M3A) and M32_Taq peptidases. The M2 peptidase angiotensin converting enzyme (ACE, EC 3.4.15.1) catalyzes the conversion of decapeptide angiotensin I to the potent vasopressor octapeptide angiotensin II. ACE is a key component of the renin-angiotensin system that regulates blood pressure, thus ACE inhibitors are important for the treatment of hypertension. M3A includes thimet oligopeptidase (TOP; endopeptidase 3.4.24.15), neurolysin (3.4.24.16), and the mitochondrial intermediate peptidase; and M3B includes oligopeptidase F. The M32 family includes eukaryotic enzymes from protozoa Trypanosoma cruzi, a causative agent of Chagas' disease, and from Leishmania major, a parasite that causes leishmaniasis, making these enzymes attractive targets for drug development. The M4 family includes secreted protease thermolysin (EC 3.4.24.27), pseudolysin, aureolysin, and neutral protease as well as bacillolysin (EC 3.4.24.28) that degrade extracellular proteins and peptides for bacterial nutrition, especially prior to sporulation. Thermolysin is widely used as a nonspecific protease to obtain fragments for peptide sequencing as well as in production of the artificial sweetener aspartame. The M13 family includes neprilysin (EC 3.4.24.11) and endothelin-converting enzyme I (ECE-1, EC 3.4.24.71), which fulfill a broad range of physiological roles due to the greater variation in the S2' subsite allowing substrate specificity and are prime therapeutic targets for selective inhibition. The peptidase M36 fungalysin family includes endopeptidases from pathogenic fungi. Fungalysin hydrolyzes extracellular matrix proteins such as elastin and keratin. Aspergillus fumigatus causes the pulmonary disease aspergillosis by invading the lungs of immuno-compromised animals and secreting fungalysin that possibly breaks down proteinaceous structural barriers.
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