Trypsin-like activity

Melanocyte stimulating hormone (a and (5forms) Endoproteinase with trypsin like activity... 

Total protein, albumin, urea (standard methods) and middle molecules (MM) were determined in citrated plasma [6]. The trypsin-like activity (TLA) of plasma was measured using the chromogenic peptide substrate (Z-glycyl-glycyl-L-arginine-4-nitroanilide) [7]. Evaluation of anti-enzymatic potential in plasma was based on concentrations of the main protease inhibitors -proteinase inhibitor (ttj-PI) and aj-macroglobulin (a -M). Student s t-test was used for statistical analysis. 

The clinical effect of Ovosorb can be attribnted to its effect on rednction of proteolytic activity in plasma and, as a resnlt, restoration of the balance between proteases and their inhibitors. Immediately after hemoperfnsion, in spite of decrease of the trypsin-like activity, the activity of protease inhibitors in plasma remained at its initial low level. This fact is in line with onr knowledge on the rates of biosynthesis of these proteins. 

The influence of the ovarian cycle on protease activity in the vagina has also been demonstrated. For example, the trypsin-like activity in rat vaginal smears was found to be maximal at proestrus. The activity of //-glucuronidase, acid phosphatase, alkaline phosphatase, and esterase all vary in the vaginal tissue of premenopausal and postmenopausal women. 

In the SI pockets of /92, no such large structural changes are noted upon the introduction of IFNy-induced subunits (/92i), as was the case with /91i. Ser-32 and Asp-53 of pi are replaced by glutamine in the pl subunit. It is conceivable that the trypsin-like activity of the pit subunit is enhanced by the acidic Glu residues, which would stabilize the basic substrate residue in the pocket. 

Since the tripeptide moieties of the inhibitor 5 were identified in all six active sites, as in the case of the acetylated tripeptide aldehyde, in the absence of substrate and at the high concentration of inhibitor used for the soaking experiments, the pi, and fS active sites are indeed insufficiently selective to discriminate the C-terminal norleucinal as the PI residue. Conversely, the bivalent inhibitor 8 containing the tripeptide aldehyde -Arg-Val-Arg-H was detected only in the two tryp-sin-like and fl active sites, despite the high concentration used. This observation confirms a significant degree of selectivity of this bivalent ligand for the trypsin-like active sites. 

It has been known that the treatment of mammalian [67, 68] or yeast proteasome [69] with larger excesses of the thiol-reagent N-ethylmaleinimide (NEM) leads to selective inhibition of the trypsin-like activity. In the crystal structure of the yeast 20S proteasome the conserved CysllS residue of the P3 subunit protrudes into the S3 sub site of the p2 active site [34], a fact that could explain the inactivation of the trypsin-like activity of proteasomes by its chemical modification with NEM. The par-... 

Purified 20S proteasome (Methanosarcina thermophila, recombinant, Escherichia coli) was purchased from Calbiochem. Purified eukaryotic 20S proteasome (from rabbit) and eukaryotic 26S proteasome (from rabbit) were purchased from Sigma. Fluorogenic peptide substrates, Suc-Leu-Leu-Val-Tyr-AMC (for the proteasomal chymotrypsin-like activity) and benzyloxycarbonyl, (Z)-Leu-Leu-Glu-AMC (for the proteasomal PGPH activity), were also obtained from Calbiochem, and Z-Gly-Gly-Arg-AMC (for the proteasomal trypsin-like activity) was purchased from Bachem (King of Prussia, PA). 

A whole cell extract (10 pg) of Jurkat T cells or HL60 cells or MCF-7 cells or U937 cells was incubated for 90 min at 37°C with 20 pM fluorogenic peptide substrate, Suc-Leu-Leu-Val-Tyr-AMC for chymotrypsin-like or Z-Leu-Leu-Glu-AMC for PGPH or Z-Gly-Gly-Arg-AMC for trypsin-like activities, in 200 pL of the assay... 

MCF7 cell extracts (10 pg/reaction) were incubated for 90 min with various fluorogenic peptide substrates for the proteasomal PGPH, chymotrypsin-Uke, trypsin-like activity with 10 pM tea polyphenols, and detected free AMC groups. 

Many studies show that the use of PCR-based molecular methods to amplify PSA-mRNA as molecular marker offer a sensitive assay for the detection of extraprostatic PSA synthesizing cells suitable for monitoring and detection of micrometastases and circulating tumor cells originated from prostatic carcinoma. The use of PSA as a molecular target proved to be more sensitive than the amplification of other prostate-specific tissue markers like prostate-specific membrane antigen (PSMA) or human glandular kallikrien (a member of the kallikrien family of serine proteases with trypsin like activity). 

The commercial 1,2,4-oxadiazole derivatives 90 have been designed, by means of a structure and ligand-based in sihco approach, as noncovalent human 20S proteasome inhibitors (2013MI2351). The lead compound 90 (Ar = 3,4-diMeOC6H3) is a mixed proteasomal inhibitor of chymo-trypsin-like activity. This compound is also selective against the difficult druggable proteases cathepsin B and calpain. 

Enzymes with trypsin like activity have been reported in some bacteria but there is no assurance that they really are trypsin.]... 

Fig. 13.4 Diagrammatic representation of the proteasome and its role in protein degradation via the uhiquitin-proteasome pathway. After being tagged with ubiquitin and unfolded for degradation on the 19S regulatory particles which aid the opening of a proteolytic gate in the 20S cote, proteins ate degraded into small peptides in the barrel-shaped core where pi caspase-, p2 trypsin-, and p5 chymo-trypsin-like activities reside. Regulatory particles are...

During the moult, chitin in the old cuticle of the insect Manduca sexta was shown to be digestive by the chitinase taken up from moulting fluid, but the chitin in intact i.e. premoult) cuticle was not accessible to chitinase. As a prerequisite of digestion, old cuticle was rendered chitinase-labile by a reaction attributable to a trypsin-like activity in the moulting fluid. 

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