Biochemical characterization of human cathepsin X revealed that the enzyme is an exopeptidase, acting as carboxymonopeptidase or carboxydipeptidase

Biochemical characterization of human cathepsin X revealed that the enzyme is an exopeptidase, acting as carboxymonopeptidase or carboxydipeptidase

Autor Klemencic, I Google Scholar
Carmona, Adriana Karaoglanovic Autor UNIFESP Google Scholar
Cezari, Maria Helena Sedenho Autor UNIFESP Google Scholar
Juliano, Maria Aparecida Autor UNIFESP Google Scholar
Juliano, Luiz Autor UNIFESP Google Scholar
Guncar, G. Google Scholar
Turk, D. Google Scholar
Krizaj, I Google Scholar
Turk, V Google Scholar
Turk, B. Google Scholar
Instituição Jozef Stefan Inst
Universidade Federal de São Paulo (UNIFESP)
Resumo Cathepsin X, purified to homogeneity from human liver, is a single chain glycoprotein with a molecular mass of approximate to 33 kDa and pI 5.1-5.3. Cathepsin X was inhibited by stefin A, cystatin C and chicken cystatin (K(i) = 1.7-15.0 nm), but poorly or not at all by stefin B (K(i) > 250 nm) and L-kininogen, respectively. the enzyme was also inhibited by two specific synthetic cathepsin B inhibitors, CA-074 and GFG-semicarbazone. Cathepsin X was similar to cathepsin B and found to be a carboxypeptidase with preference for a positively charged Arg in P1 position. Contrary to the preference of cathepsin B, cathepsin X normally acts as a carboxymonopeptidase. However, the preference for Arg in the P1 position is so strong that cathepsin X cleaves substrates with Arg in antepenultimate position, acting also as a carboxydipeptidase. A large hydrophobic residue such as Trp is preferred in the P1' position, although the enzyme cleaved all P1' residues investigated (Trp, Phe, Ala, Arg, Pro). Cathepsin X also cleaved substrates with amide-blocked C-terminal carboxyl group with rates similar to those of the unblocked substrates. in contrast, no endopeptidase activity of cathepsin X could be detected on a series of o-aminobenzoic acid-peptidyl-N-[2,-dinitrophenyl]ethylenediamine substrates. Furthermore, the standard cysteine protease methylcoumarine amide substrates (k(cat)/K(m) approximate to 5.0 x 10(3) m(-1).s(-1)) were degraded approximate to 25-fold less efficiently than the carboxypeptidase substrates (k(cat)/K(m) approximate to 120.0 x 10(3) m(-1).s(-1)).
Palavra-chave cathepsin
cysteine protease
carboxypeptidase
exopeptidase
cystatin
Idioma Inglês
Data de publicação 2000-09-01
Publicado em European Journal of Biochemistry. Malden: Wiley-Blackwell, v. 267, n. 17, p. 5404-5412, 2000.
ISSN 0014-2956 (Sherpa/Romeo, fator de impacto)
Publicador Wiley-Blackwell
Extensão 5404-5412
Fonte http://dx.doi.org/10.1046/j.1432-1327.2000.01592.x
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000089101400018
Endereço permanente http://repositorio.unifesp.br/handle/11600/26361

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