Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pattern of development of antibody-forming cells in BALB/c mice after immunization with PW-LPS or TCA-LPS was shown to be different. On days 10 and 20, the primary response to PW-LPS was characterized by a low level of IgM synthesis. The plaque-forming cell (PFC) response to TCA-LPS, however, increased from day 10 to day 20. Initially, IgM was the only detectable antibody synthesized but by day 20 a significant number of IgG-producing spleen cells had developed. After a secondary immunization with the appropriate lipopolysaccharide (LPS) preparation, IgG-producing spleen cells were detected in mice immunized with either PW-or TCA-LPS. Partial removal of the LAP or TCA-LPS with phenol or trypsin and pronase significantly reduced the PFC response, suggesting that the protein moiety played an influential role in the immunogenicity of TCA-LPS. The TCA-LPS contained the same antigenic dterminants as PW-LPS, so any difference observed between PFC response was not due to any associated immunogenic moiety.
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PMID:Plaque-forming cell response in BALB/c mice to two preparations of LPS extracted from Salmonella enteritidis. 8 28

Aminopeptidases catalyze the hydrolysis of amino acid residues from the amino terminus of peptide substrates. They are found in most cells and tissues, and their activity has been implicated in myriad fundamental biochemical and physiological processes. Nevertheless, little is known about the structure of the aminopeptidase active sites. Beef lens leucine aminopeptidase (blLAP) can be considered prototypical of many enzymes in this family of peptidases. Bestatin, [(2S,3R)-(3-amino-2-hydroxy-4-phenyl-butanoyl)-L-leucine] is a nonhydrolyzable substrate analogue of a peptide, PheLeu, which is rapidly cleaved by blLAP. Bestatin incorporates elements of the putative tetrahedral intermediate, and this results in a greater than 10(5)-fold enhancement of binding relative to analogous peptides. Bestatin is the most tightly bound inhibitor of many aminopeptidases. Bestatin was successively converted to nitrobestatin, p-aminobestatin, [3H]-p-aminobestatin, and finally [3H]-p-azidobestatin (pAB). Like bestatin, pAB is a slow binding inhibitor of LAP (Ki*, the dissociation constant for the final complex, = approximately 4 x 10(-9); Ki, the dissociation constant for the initial collision complex, = approximately 10(-8). The t1/2 for binding of 2 x 10(-8) M and 8 x 10(-8) M bestatin are approximately 60 min and approximately 38 min, respectively. pAB, nitrobestatin, bestatin, and physiological peptides appear to bind in the same site, the first three with similar avidity. In the dark, pAB and bestatin protect low concentrations of the enzyme against inactivation upon extensive dialysis. The t1/2 for photoactivation of pAB is approximately 3 s. Irradiation of blLAP for such short periods of time resulted in insignificant change in activity. blLAP which was placed in 254-nm light in the presence of pAB was inactivated significantly. Treatment of photolabeled blLAP with trypsin produces only two peptides. Autoradiography and scintillation counting indicate that the active site is in the peptide which includes residues 138-487. Treatment of the same blLAP with hydroxylamine produces two different peptides, with the active site in the peptide 323-487. This indicates that the active site is in the carboxyl-terminal one-third of the protomer. It is likely that this photoaffinity label will be useful in identifying active sites in other aminopeptidases as well.
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PMID:Use of azidobestatin as a photoaffinity label to identify the active site peptide of leucine aminopeptidase. 156 60

Non-phosphorylative transglucosylation, GGT and LAP activity, the level of some "acute phase" proteins i.e. sialic acids, ceruloplasmin, papain and trypsin inhibitors were examined in the serum, normal myometrium around tumours and in the uterine myoma of women. It was observed that the contents of proteins in the "acute phase" as well as GGT and LAP activity increased in the serum, whereas a decreased activity of these enzymes accompanied by increased transferase activity was observed in uterine myoma.
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PMID:Non-phosphorylative transglucosylation and other biochemical indices in serum and uterine myoma in women. 172 93

A chemically synthesized gene, which encodes a 64 or 128 times-repeated tripeptide, aspartyl-phenylalanyl-lysine, has been cloned onto the yeast expression vector pAM82 containing the PHO5 promoter. The artificial gene (LAP gene) contains the untranslated leader sequence of the E. coli lipoprotein gene (lpp) with its transcription terminator sequence. When yeast AH22 cells transformed by recombinant plasmid containing repeated tripeptide gene were derepressed in low phosphate medium, the artificial polypeptides were synthesized to the amounts of about 30% of the total cell protein. SDS-polyacrylamide gel electrophoresis and immunoblot analysis indicated that the artificial polypeptides synthesized in yeast have molecular weights ranging from about 30,000 and 60,000 and have immunoreactivity with the artificial polypeptides expressed in E. coli. The artificial popypeptides in whole cell extract were insoluble and seem to be synthesized as insoluble aggregates. Electron microscopy showed the presence of inclusion bodies in the cell. These polypeptides can be hydrolyzed to tripeptides with trypsin or chymotrypsin. These properties along with the high expression and easy separation may make the artificial polypeptides a potential raw material for the production of an artificial sweetener, Aspartame.
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PMID:High level expression in Saccharomyces cerevisiae of an artificial gene encoding a repeated tripeptide aspartyl-phenylyalanyl-lysine. 776 34

Potato protease inhibitors, POT-1 and POT-2, were fed to newly emerged adult honey bees in cages at different doses in either sugar syrup (0.2 or 0.01% w:v) or pollen food (1 or 0.2% w:w). In vivo activities of three digestive endopeptidases (trypsin, chymotrypsin and elastase) and one exopeptidase (leucine aminopeptidase; LAP) were measured after 3 or 8days' exposure of bees to inhibitor. Enzyme activities were significantly lower at day 8 than at day 3, except for elastase, which did not change. POT-2 significantly reduced the activity of all endopeptidases at both timepoints, regardless of the dose level or the medium in which the inhibitor was administered. POT-1 acted in a similar manner, except that 0.01% POT-1 in syrup had no effect on bees. There was no consistent trend in changes in LAP activity. Bees fed either inhibitor at 1% in pollen or at 0.2% in syrup had significantly reduced lifespans, with the effect of the pollen treatment being greater than the syrup treatment. The survival of bees fed POT-1 or POT-2 at 0.2% in pollen or 0.01% in syrup did not differ from the controls.
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PMID:In vivo Responses of Honey Bee Midgut Proteases to Two Protease Inhibitors from Potato. 1276 86