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Aminopeptidase PC from the hepatopancreas of the Kamchatka crab Paralithodes camtshatica.
Rudenskaya, G N; Shmoilov, A M; Isaev, V A; Ksenofontov, A V; Shvets, S V.
Afiliação
  • Rudenskaya GN; School of Chemistry, Lomonosov Moscow State University, Moscow, 119899, Russia. Rudenskaya@biorg.msu.su.
Biochemistry (Mosc) ; 65(2): 164-70, 2000 Feb.
Article em En | MEDLINE | ID: mdl-10713541
ABSTRACT
Homogeneous aminopeptidase PC was isolated with yield 67% and purification degree 237 from the hepatopancreas of the Kamchatka crab Paralithodes camtshatica by ion-exchange chromatography on DEAE-Sepharose, hydrophobic chromatography on Phenyl-Sepharose, and gel-filtration on Sephadex G-150. The enzyme is a homodimer with a molecular mass 220 kD (110 x 2). Aminopeptidase PC has pI = 4.1. It hydrolyzes Leu-pNA optimally at pH 6.0 and at the optimum temperature 36-40 degrees C; in the presence of Ca2+ the enzyme is stable at pH 5.5-8.0. Aminopeptidase PC is activated by Ca2+, Mg2+, and Fe2+; it is completely inhibited by EDTA, o-phenanthroline, and bestatin. The enzyme contains four Zn atoms per molecule and is therefore a metalloaminopeptidase. The aminopeptidase PC can effectively cleave N-terminal Arg and Lys residues as well as Leu, Phe, and Met residues. Km and kcat values for hydrolysis of Leu-pNA were 0.075 mM and 0.19 sec-1 and for hydrolysis of Arg-pNA 0.078 mM and 0.48 sec-1, respectively. D-Amino acid residues cannot be cleaved. Thus, aminopeptidase PC of the Kamchatka crab has a mixed substrate specificity which is characteristic of some microbe aminopeptidases. Its N-terminal sequence ESVEIELPEGLSPLV is 46% coincident with that of yeast vacuolar aminopeptidase YSCA.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Braquiúros / Aminopeptidases Limite: Animals Idioma: En Revista: Biochemistry (Mosc) Ano de publicação: 2000 Tipo de documento: Article
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Braquiúros / Aminopeptidases Limite: Animals Idioma: En Revista: Biochemistry (Mosc) Ano de publicação: 2000 Tipo de documento: Article