Data/hora: 23/05/2024 13:41:59

Provedor de dados: | 56
País: | Brazil
Título: | The role of autolysis loop in determining the specificity of coagulation proteases
Autores: | Yang,L.; Manithody,C.; Rezaie,A.R.
Data: | 2007-08-01
Ano: | 2007
Palavras-chave: | Activated protein C; Factor Va; Antithrombin; Factor Xa; Serpins.
Resumo: | We recently demonstrated that the substitution of the autolysis loop (residues 143 to 154 in the chymotrypsin numbering system) of activated protein C (APC) with the corresponding loop of factor Xa (fXa) renders the APC mutant (APC/fX143-154) susceptible to inhibition by antithrombin (AT) in the presence of pentasaccharide. Our recent results further indicated, that in addition to an improvement in the reactivity of APC/fX143-154 with AT, both the amidolytic and anti-factor Va activities of the mutant APC have also been significantly increased. Since the autolysis loop of APC is five residues longer than the autolysis loop of fXa, it could not be ascertained whether this loop in the mutant APC specifically interacts with the activated conformation of AT or if a shorter autolysis loop is responsible for a global improvement in the catalytic activity of the mutant protease. To answer this question, we prepared another APC mutant in which the autolysis loop of the protease was replaced with the corresponding loop of trypsin (APC/Tryp143-154). Unlike an ~500-fold improvement in the reactivity of APC/fX143-154 with AT in the presence of pentasaccharide, the reactivity of APC/Tryp143-154 with the serpin was improved ~10-fold. These results suggest that both the length and structure of residues of the autolysis loop are critical for the specificity of the coagulation protease interaction with AT. Further factor Va inactivation studies with the APC mutants revealed a similar role for the autolysis loop of APC in the interaction with its natural substrate.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2007000800005
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X2006005000137
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.40 n.8 2007
Fonte: | info:eu-repo/semantics/openAccess