Cattle tick Boophilus microplus salivary gland contains a thiol-activated metalloendopeptidase displaying kininase activity.

Michele Bastiani, Sandro Hillebrand, Fabiana Horn, Tarso Benigno Ledur Kist, Jorge Almeida Guimarães, Carlos Termignoni

Centro de Biotecnologia, Universidade, Departamento de Biofísica, Universidade Federal do Rio Grande do Sul. Caixa Postal 15005, 91501-970, Porto Alegre, Brazil.

Insect biochemistry and molecular biology 2002 Nov

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This work reports on the characterization of a metalloendopeptidase kininase present in Boophilus microplus salivary glands. Using the guinea pig ileum assay, salivary gland whole extracts (SGE) were found to have a potent kininase activity. Ion-exchange chromatography separated two kininase activities from SGE. The major enzymatic component, eluted at lower ionic strength, was named BooKase (Boophilus Kininase). Analysis of the hydrolysis products by capillary electrophoresis identified Phe5-Ser6 as the only hydrolyzable peptide bond in bradykinin after BooKase treatment. This is the same specificity as the mammalian thimet oligoendopeptidase (EC 3.4.24.15). Like this enzyme, BooKase is also a metallo-peptidase (requires Mn2+) and is activated by-SH protecting reagents. In addition, BooKase was partially inhibited by cFP-AAF-pAB, a specific inhibitor of thimet oligopeptidase. Contrary to other kininases, BooKase had no activity upon angiontensin I. Our results show that BooKase behaves as a typical peptidase with kinase activity.

Citation

Michele Bastiani, Sandro Hillebrand, Fabiana Horn, Tarso Benigno Ledur Kist, Jorge Almeida Guimarães, Carlos Termignoni. Cattle tick Boophilus microplus salivary gland contains a thiol-activated metalloendopeptidase displaying kininase activity. Insect biochemistry and molecular biology. 2002 Nov;32(11):1439-46