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From Proteopedia
SERRATIA PROTEASE IN COMPLEX WITH INHIBITOR
Structural highlights
Function[PRZN_SERMA] Has insecticidal activity against the locust M.palpalis. When administered orally to locusts at a low dose it causes them to lie on their sides exhibiting sporadic limb movements and muscular twitching, followed by full recovery. When administered at higher doses the same symptoms are observed, followed by death. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSubstrates HO2CCH2CH2CO- and HOCH2CHOHCHOHCO-Phe-Leu-Ala-5-nitro-2-pyridinamide are cleaved efficiently at the acylarenamide linkage, with a convenient spectrophotometric assay, by the Serratia and Pseudomonas approximately 50-kDa extracellular metalloproteases (serralysins). The pH range of catalytic activity extends uniformly from 4 to greater than 10 (k(cat)/Km approximately 10(3) s(-1) M(-1), similar profile for k(cat)). Substrate analogue hydroxamic acid Cbz-Leu-Ala-NHOH competitively inhibits serralysin (Ki 0.04 mM), with a pH dependence indicating that either a displaced metal-bound H2O or a similarly motile enzymic phenol residue (Tyr216) that is crystallographically found ligated to the active-site Zn2+ of the uncomplexed enzyme must have a pKa of approximately 5. A chemical catalytic mechanism of proteolysis consistent with the kinetic data is proposed, in which Tyr216-ArO-, in the course of being released from the active-site metal ion, deprotonates a water molecule attacking the Zn2+-activated substrate linkage, leading to a metal-coordinated tetrahedral oxyanion adduct that subsequently fragments. Kinetic characterization of the serralysins: a divergent catalytic mechanism pertaining to astacin-type metalloproteases.,Mock WL, Yao J Biochemistry. 1997 Apr 22;36(16):4949-58. PMID:9125517[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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