Enzyme-substrate binding constants, K’e, for chymotrypsin and specific amide (N-acetyl-Mryptophanamide and Nacetyl-L-phenylalaninamide) and ester (N-acetyl-L-tryptophan ethyl ester) substrates have been measured by a proflavin-displacement method. Also, the rate constant for the formation of one intermediate in the chymotrypsincatalyzed hydrolysis of the ester has been determined at selected pH...

Guanylin and uroguanylin are small cysteine-rich peptides involved in the regulation of fluid and electrolyte homeostasis through binding and activation of guanylyl cyclases signaling molecules expressed in intestine and kidney. Guanylin is less potent than uroguanylin as a natriuretic agent and is degraded in vitro by chymotrypsin due to unique structural features in the bioactive moiety of th...

a-Chymotrypsin and trypsin were spin-labeled with 14 ortho-, meta-, and para-substituted phenylsulfonyl fluorides. These analogues of tosylfluoride were substituted with either pyrrolidinyl, pyrrolinyl, or piperidinyl nitroxide moieties. A complete description of their synthesis and the enzyme inhibition studies is presented in the following paper (WONG, S. S., QUIGGLE, K., TRIPLETT, C., AND BE...

An appropriate in vitro starch digestion model is necessary to comparatively evaluate the digestibility of starch samples and to help predict the in vivo glycemic responses of starchy foods. In the present study, the effect of trypsin and chymotrypsin on in vitro digestion of rice starch was studies for the first time. Inclusion of the trypsin and chymotrypsin in the digestion protocols, to mor...

Several esters of 4-methylumbelliferone and 2-naphthol were synthesized and examined as possible spectrofluorimetric titrants for bovine alpha-chymotrypsin, trypsin, thrombin, Factor Xa and for subtilisin Novo. 4-Methylumbelliferyl p-guanidinobenzoate hydrochloride (MUGB) is a satisfactory titrant for alpha- and beta-trypsin, thrombin and Factor Xa and 4-methylumbelliferyl p-(NNN-trimethylammon...

Mono[14C]acetyl-chymotrypsin was prepared by treating alpha-chymotrypsin with a 10-fold molar excess of p-nitrophenyl[14C]acetate at pH 5, and the acetylated enzyme was isolated free of excess reagents by gel filtration. Deacetylation at pH 6.0 was followed by observing the decrease in acid-precipitable radioactivity and provided a first-order rate constant of 0.02 +/- 0.008 min-1. Reactivation...

SLPI (secretory leukocyte protease inhibitor) is a 107-residue protease inhibitor which inhibits various serine proteases, including elastase, cathepsin G, chymotrypsin and trypsin. SLPI is obtained as a multiple inhibitor in lung defense and in chronic airway infection. X-ray crystal structures have so far reported that they are full-length SLPIs with bovine α-chymotrypsin and 1/2SLPI (recombi...

This paper reports on the presence of a strong binding site for the dye Biebrich Scarlet, (6-[Z-hydroxy-l-naphthyl]azo)3,4’-azodibenzene sulfonic acid, on cr-chymotrypsin. The 1: 1 protein-dye complex is characterized by a Kdiss of 8.8 f 0.1 X 10U5 M in 0.1 M phosphate buffer at pH 7.6 and W’. Complex formation is associated with a red shift in the visible spectrum of the dye, and a characteris...

The proteasome, a validated anticancer target, participates in an array of biochemical activities, which range from the proteolysis of defective proteins to antigen presentation. We report the preparation of biochemically and photophysically distinct green, red, and far-red real-time sensors designed to simultaneously monitor the proteasome's chymotrypsin-, trypsin-, and caspase-like activities...

Eglin c, turkey ovomucoid third domain, and bovine pancreatic trypsin inhibitor (Kunitz) are all standard mechanism, canonical protein inhibitors of serine proteinases. Each of the three belongs to a different inhibitor family. Therefore, all three have the same canonical conformation in their combining loops but differ in their scaffoldings. Eglin c (Leu45 at P1) binds to chymotrypsin much bet...