Hydrolysis of synthetic peptides by cruzipain, the major cysteine proteinase from Trypanosoma cruzi, provides evidence for self-processing and the possibility of more specific substrates for the enzyme

Autor: J J, Cazzulo, M, Bravo, A, Raimondi, U, Engström, G, Lindeberg, U, Hellman
Rok vydání: 1996
Předmět:
Zdroj: Cellular and molecular biology (Noisy-le-Grand, France). 42(5)
ISSN: 0145-5680
Popis: Two synthetic peptides, peptide G, with the sequence KEEASSAVVGGPG, consisting of the last 10 amino acid residues of the catalytic domain, plus the first 3 at the C-terminal domain, of cruzipain, and peptide R, with the sequence KEEASSAVVRGPG, were hydrolyzed by the enzyme, as shown by reversed-phase HPLC. Peptide R was the best substrate, with a Vmax/K(m) ratio 6-fold higher as compared with peptide G, in good agreement with previous studies indicating that, in small peptides, cruzipain prefers R or K at P1. The optimal pH values for hydrolysis of peptides G and R were 6.8 and 8.0, respectively. A p-nitroanilide derivative containing the P1-P3 residues, Z-VVR-pNA, was an excellent substrate for cruzipain, with a K(m) value (33 microM at pH 9.0) lower than that for Bz-PFR-pNA (66 microM). These results open the possibility of synthesizing more specific substrates and inhibitors of cruzipain.
Databáze: OpenAIRE