To explore the possible role of proteolytic step(s) in receptor-mediated endocytosis of insulin, the effects of inhibitors of various classes of proteases on the internalization process were studied in isolated rat adipocytes. Intracellular accumulation of receptor-bound 125I-insulin at 37 degrees C was quantitated after rapidly dissociating surface-bound insulin with an acidic buffer (pH 3.0)....

Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory autoimmune diseases of the central nervous system. Chymotrypsin is a serine protease with immunomodulatory effect in the peripheral organs. We previously demonstrated the immunomodulatory effect of chymotrypsin in ameliorating the EAE in female Lewis rats. However, there are sex-based...

Proteinase treatment with chymotrypsin has been used to probe the structure of native Klebsiella pneumoniae nitrogenase MoFe protein (Kp1). Reaction with chymotrypsin did not bleach Kp1, suggesting that it did not destroy the metal centres, and the Mo and Fe contents of Kp1 were unchanged. High ratios of chymotrypsin to Kp1 (1:1 by mass) cleaved the beta-chain of Kp1 to give 44 and 14 kDa polyp...

Single-molecule studies allow the study of subtle activity differences due to local folding in proteins, but are time consuming and difficult because only a few molecules are observed in one experiment. We developed an assay where we can simultaneously measure the activity of hundreds of individual molecules. The assay utilizes a synthetic chymotrypsin substrate that is nonfluorescent before cl...

Subtilisin BPN' hydrolysed N-acetyl-l-3-(2-naphthyl)-alanine methyl ester, N-acetyl-l-leucine methyl ester and N-acetyl-l-valine methyl ester, faster than alpha-chymotrypsin. Of eight ;locked' substrates tested, only methyl 5,6-benzindan-2-carboxylate was hydrolysed faster by subtilisin, whereas the other esters were better substrates for chymotrypsin. Compared with the values for chymotrypsin,...

The preparation of a new stable and active form of chymotrypsin is described. The enzyme possesses threonine-147 instead of alanineas the NH&erminal group of the C chain and has been called ai-chymotrypsin. The conformational transition that affects chymotrypsins at alkaline pH was investigated and compared with that of 01and &chymotrypsins by studying the kinetic constants and their pH depende...

I.r. difference spectroscopy combined with 13C and 18O double-isotope substitution was used to examine the ester acyl carbonyl stretching vibration of hydrocinnamoyl-chymotrypsin. A single acyl carbonyl stretching band was observed at 1731 cm-1. This contrasts with previous i.r. and resonance Raman spectroscopic studies of a number of trans-3-arylacryloyl-chymotrypsins which showed two acyl car...

The determination of three separate y-chymotrypsin structures a t different temperatures and resolutions confirmed the presence of electron density in the active site, which could be interpreted as an oligopeptide as had previously been suggested by Dixon and Matthews [( 1989) Biochemistry 28,7033-70381. HPLC analyses of the enzyme before and after crystallization demonstrated the presence of a...

The legume-derived Bowman-Birk trypsin and chymotrypsin protease inhibitors (BBI) are effective anticarcinogens in vivo and in vitro. The chymotrypsin-inhibitory domain has been shown to be responsible for this anticarcinogenic action. In this study we identify hydrolytic enzymes by their ability to hydrolyze the relatively specific chymotrypsin substrate succinyl-Ala-Ala-Pro-Phe-aminomethyl co...

: Chymotrypsin- or trypsin V- (a mixture of trypsin and chymotrypsin) digested beta-lactoglobulin (BLG) peptides were prepared and were confirmed to have much less immunoglobulin (lg)G and lgE reactivity compared with intact BLG by IgG inhibition enzymelinked immunosorbent assay and IgE dot blotting. The lymphocyte responses to intact BLG and these peptides were examined using peripheral blood ...