The geometry of the binary and ternary complexes of two black-eyed pea inhibitors with trypsin and chymotrypsin has been established by distance measurements using the technique of singlet-singlet energy transfer. Triangulation of measured distances in the ternary double-headed complex of the trypsin-chymotrypsin inhibitor (BEPCI) with trypsin and chymotrypsin limits the possible structural mod...

The data indicate that trypsin-Sepharose has markedly different inhibition kinetics from trypsin in free solution. The Sepharose granules (i) offer protection from inhibition in the first place (e.g. for active-site titrants; Fig. Id) and/or (ii) facilitate the displacement of inhibitor from trypsin by excess substrate (Figs. la, Ib and Ic). It would seem that when an inhibitor such as ovomucoi...

A nutrition study was conducted to evaluate the growth response of weaned piglets fed diets containing soya beans that had been processed into protein supplements at two different levels of dry matter (DM) and temperature. Four diets contained protein supplements prepared from whole full-fat soya beans equilibrated at 800 or 900 g kgÿ1 DM prior to being heated to 110 or 1258C. An additional die...

The physiology of the gut lumen of the red flour beetle, T. castaneum, was studied to determine the conditions for optimal protein hydrolysis. Although the pH of gut lumen extracts from T. castaneum was 6.5, maximum hydrolysis of casein by gut proteinases occurred at pH 4.2. The synthetic substrate N-alpha-benzoyl-DL-arginine-rho-nitroanilide was hydrolyzed by T. castaneum gut proteinases in bo...

The Kunitz-type protease inhibitors are the best-characterized family of serine protease inhibitors, probably due to their abundance in several organisms. These inhibitors consist of a chain of ~60 amino acid residues stabilized by three disulfide bridges, and was first observed in the bovine pancreatic trypsin inhibitor (BPTI)-like protease inhibitors, which strongly inhibit trypsin and chymot...

Purified al-proteolytic inhibitor from human plasma was shown to inhibit trypsin, chymotrypsin, plasmin, and thrombin. This inhibitor is probably identical with the inhibitor previously known as serum trypsin inhibitor, al-antitrypsin, or antiplasmin. The enzymes were affected by the inhibitor via two different mechanisms. Trypsin and chymotrypsin reacted instantaneously in stoichiometric manne...

In a previous study, a genetic screening procedure was used to identify variants of bovine pancreatic trypsin inhibitor that can fold to an active conformation but that are inactivated much more rapidly than the wild-type protein in the presence of dithiothreitol (DTT). The mechanisms by which 30 of these DTT-sensitive variants are inactivated have now been investigated. Some of the amino acid ...

Sea anemones are a rich source of Kunitz-type polypeptides that possess not only protease inhibitor activity, but also Kv channels toxicity, analgesic, antihistamine, and anti-inflammatory activities. Two Kunitz-type inhibitors belonging to a new Heteractis crispa RG (HCRG) polypeptide subfamily have been isolated from the sea anemone Heteractis crispa. The amino acid sequences of HCRG1 and HCR...