TL;DR: Preliminary studies indicate that benzoyl dl -arginine p -nitroanilide hydrochloride is also hydrolyzed by papain, and that of l -LPA is in a more alkaline region than normally found for trypsin substrates.
TL;DR: Crystalline soy protein when denatured is readily digestible by pepsin, and less readily by chymotrypsin and by trypsin, which results in a proportional gain in the inhibiting activity.
Abstract: A study has been made of the general properties of crystalline soybean trypsin inhibitor. The soy inhibitor is a stable protein of the globulin type of a molecular weight of about 24,000. Its isoelectric point is at pH 4.5. It inhibits the proteolytic action approximately of an equal weight of crystalline trypsin by combining with trypsin to form a stable compound. Chymotrypsin is only slightly inhibited by soy inhibitor. The reaction between chymotrypsin and the soy inhibitor consists in the formation of a reversibly dissociable compound. The inhibitor has no effect on pepsin. The inhibiting action of the soybean inhibitor is associated with the native state of the protein molecule. Denaturation of the soy protein by heat or acid or alkali brings about a proportional decrease in its inhibiting action on trypsin. Reversal of denaturation results in a proportional gain in the inhibiting activity. Crystalline soy protein when denatured is readily digestible by pepsin, and less readily by chymotrypsin and by trypsin. Methods are given for measuring trypsin and inhibitor activity and also protein concentration with the aid of spectrophotometric density measurements at 280 mmicro.
TL;DR: The spectrophotometric procedure proposed by Schwert and Takenaka has been modified and extended to include the application to N-benzoyl-L-tyrosine ethyl ester and α-p-toluenesulphonyl- L-arginine methyl ester, allowing the determination of traces of chymotrypsin in the presence of relatively large amounts of trypsin.
Abstract: The spectrophotometric procedure proposed by Schwert and Takenaka for the assay of chymotrypsin and trypsin has been modified and extended to include the application to N-benzoyl-L-tyrosine ethyl e...
TL;DR: X-ray crystal structure analysis, molecular modelling, and protein digest data indicate that the Arg 117 residue is a trypsin-sensitive site, and that loss of this cleavage site would permit autodigestion resulting in pancreatitis.
Abstract: Hereditary pancreatitis (HP) is a rare, early-onset genetic disorder characterized by epigastric pain and often more serious complications. We now report that an Arg–His substitution at residue 117 of the cationic trypsinogen gene is associated with the HP phenotype. This mutation was observed in all HP affected individuals and obligate carriers from five kindreds, but not in individuals who married into the families nor in 140 unrelated individuals. X-ray crystal structure analysis, molecular modelling, and protein digest data indicate that the Arg 117 residue is a trypsin-sensitive site. Cleavage at this site is probably part of a fail-safe mechanism by which trypsin, which is activated within the pancreas, may be inactivated; loss of this cleavage site would permit autodigestion resulting in pancreatitis.