S(1)' and S(2)' subsite specificities of human plasma kallikrein and tissue kallikrein 1 for the hydrolysis of peptides derived from the bradykinin domain of human kininogen

The S(1)' and S(2)' subsite specificities of human tissue kallikrein 1 (KLK1) and human plasma kallikrein (HPK) were examined with the peptide series Abz-GFSPFRXSRIQ-EDDnp and Abz-GFSPFRSXRIQ-EDDnp [X=natural amino acids or S( PO 3 H 2) x. KLK1 efficiently hydrolyzed most of the peptides except those containing negatively charged amino acids at P 19 and P 29 positions. Abz-GFSPFRSSRIQ-EDDnp, as in human kininogen, is the best substrate for KLK1 and exclusively cleaved the R-S bond. All other peptides were cleaved also at the F-R bond. the synthetic human kininogen segment Abz-MISLMKRPPGFSPFRS(390)S(391)RI-NH(2) was hydrolyzed by KLK1 first at R-S and then at M-K bonds, releasing Lys-bradykinin. in the S(390) and S(391) phosphorylated analogs, this order of hydrolysis was inverted due to the higher resistance of the R-S bond. Abz-MISLMKRPPGFSPFRSS(PO(3)H(2))(391)RI-NH(2) was hydrolyzed by KLK1 at M-K and mainly at the F-R bond, releasing des-(Arg(9))-Lys-Bk which is a B1 receptor agonist. HPK cleaved all the peptides at R and showed restricted specificity for S in the S(1)' subsite, with lower specificity for the S(2)' subsite. Abz-MISLMKRPPGFSPFRSSRI-NH(2) was efficiently hydrolyzed by HPK under bradykinin release, while the analogs containing S(PO(3)H(2)) were poorly hydrolyzed. in conclusion, S(1)' and S(2)' subsite specificities of KLK1 and HPK showed peculiarities that were observed with substrates containing the amino acid sequence of human kininogen.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Biophys, Escola Paulista Med, BR-0404420 São Paulo, BrazilFlorida State Univ, Dept Biomed Sci, Coll Med, Tallahassee, FL 32306 USAUniversidade Federal de São Paulo, Dept Biophys, Escola Paulista Med, BR-0404420 São Paulo, BrazilWeb of Scienc