A heme-binding aspartic proteinase from the eggs of the hard tick Boophilus microplus

A heme-binding aspartic proteinase from the eggs of the hard tick Boophilus microplus

Autor Sorgine, MHF Google Scholar
Logullo, C. Google Scholar
Zingali, R. B. Google Scholar
Paiva-Silva, G. O. Google Scholar
Juliano, Luiz Autor UNIFESP Google Scholar
Oliveira, P. L. Google Scholar
Instituição Universidade Federal do Rio de Janeiro (UFRJ)
Universidade Federal de São Paulo (UNIFESP)
Universidade Federal Fluminense (UFF)
Resumo An aspartic proteinase that binds heme with a 1:1 stoichiometry was isolated and cloned from the eggs of the cattle tick Boophilus microplus. This proteinase, herein named THAP (tick heme-binding aspartic proteinase) showed pepstatin-sensitive hydrolytic activity against several peptide and protein substrates, Although hemoglobin was a good substrate for THAP, low proteolytic activity was observed against globin devoid of the heme prosthetic group. Hydrolysis of globin by THAP increased as increasing amounts of heme were added to globin, with maximum activation at a heme-to-globin 1:1 ratio. Further additions of heme to the reaction medium inhibited proteolysis, back to a level similar to that observed against globin alone. the addition of heme did not change THAP activity toward a synthetic peptide or against ribonuclease, a non-hemeprotein substrate. the major storage protein of tick eggs, vitellin (VT), the probable physiological substrate of THAP, is a hemeprotein. Hydrolysis of VT by THAP was also inhibited by the addition of heme to the incubation media. Taken together, our results suggest that THAP uses heme bound to VT as a docking site to increase specificity and regulate VT degradation according to heme availability.
Idioma Inglês
Data de publicação 2000-09-15
Publicado em Journal of Biological Chemistry. Bethesda: Amer Soc Biochemistry Molecular Biology Inc, v. 275, n. 37, p. 28659-28665, 2000.
ISSN 0021-9258 (Sherpa/Romeo, fator de impacto)
Publicador Amer Soc Biochemistry Molecular Biology Inc
Extensão 28659-28665
Fonte http://dx.doi.org/10.1074/jbc.M005675200
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000089330700044
Endereço permanente http://repositorio.unifesp.br/handle/11600/26383

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