Proteinase inhibitors in Brazilian leguminosae

Serine proteinase inhitors, in the seeds of several Leguminosae from the Pantanal region (West Brazil), were studied using bovine trypsin, a digestive enzyme, Factor XIIa and human plasma Kallikrein, two blood clotting factors. The inhibitors were purified from Enterolobium contortisiliquum (Mr=23,000), Torresea cearensis (Mr = 13,000), Bauhinia pentandra (Mr = 20,000) and Bauhinia bauhinioides (Mr = 20,000). E. contortisiliquum inhibitor inactivates all three enzymes, whereas the T. cearensis inhibitor inactivates trypsin and Factor XSSa, but does nor affect plasma kallikrein; both Bauhinia inhibitors, on the other hand, inactivate trypsin and plasma kallikrein but only the Bpentandra inhibitor affects Factor XIIa. Ki values were calculated between 10 [raised to the power of] -7 and 10 [raised to the power of] -8 M.

A Bothrops jararaca plasma cysteine proteinase inhibitor related to Mammalian kininogen

A kininogen-like protein was purified from Bothrops jararaca plasma by DEAE-Sephadex ion-exchange and carboxy-methul-papain-Sepharose affinity chromatography. The molecular weight, estimated by SDS-gel electrophoresis, is about 100,000 and a species of about 75,000 is formed after incubation with hosrse urinary kallikrein. After incubation with rrypsin, only traces of biological activity were detected in tests on guinea pig ileum. The purified protein inhibits papain and bromelain, does not correct the clotting time of a kininogen-depleted human plasma, and does not affect the clotting time ogf plasma from Waglerophis merremii, a nonpoisonous snake; the same type of inhibitor was foind in this nonpoisonous snake. The dissociation cosntant (Ki) for the papain-inhibitor complex is approximately 1.6 nM

Purification and preliminary characterization of Torresea cearensis trypsin inhibitor

An inhibitor against serine proteinases was purified from Torresea cearensis by affinity chromatography on trypsin-Sepharose. The protein is a single polypeptide of molecular weight 13,600 after reduction and has a high content of cysteine residues. Both trypsin (Ki = 0.34 nM) and chymotrypsin (Ki = 0.15 micronM) are inhibited by Torresea cearensis inhibitor. Blood clotting factor XII is also inhibited (Ki = 24 micronM), but not plasma kallikrein, tissue kallikrein or thrombin. The stoichiometry of the inhibitorproteinase complex with trypsin is 1:1

Serine and SH-proteinase inhibitors from Enterolobium contortisiliquum beans: purification and preliminary characterization

Two types inhibitors were prufied from Enterolobium contortisiliquum beans. The inhibitor of serine-proteinases inhibited trypasin (Ki = 5 nM) chymostrypsin (Ki = 10 nM) and plasma kallikrein, but not tissue kallikreins. The molecular weight is approximately 23 KDal and two polypeptide chains detected after reduction. The second inhibitor with activity directed against SH-proteinase was isolated by CM-papain-Sepharose. The molecular weight is approximately 60 KDal and only one polupeptide chain was detected after reduction. Papain (Ki = 0.6 nM) and bromelain are inhibited