Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The inhibitory behavior of flavonoids against trypsin and leucine aminopeptidase followed sigmoidal curves similar to those of any dose-biological response relationship. Statistical analysis using several mathematical equations showed that the relationship may be expressed by a logistic equation, which yielded a high correlation between the experimental data and the predicted results, together with an objective criterion for estimating the IC50 value. Flavones and flavonols exhibited a strong inhibitory effect on trypsin; the presence of hydroxyl groups at positions C-5 and C-7 in ring A is necessary for inhibition of the enzyme, while the simultaneous presence of free hydroxyl groups at positions C-3' and C-4' enhances the inhibitory activity. Inhibition of leucine aminopeptidase by flavonoids does not require 5,7-hydroxylation, but dihydroxylation at C-3' and C-4' and a double bond at positions C-2, C-3 are essential for this activity.
...
PMID:Flavonoid inhibitors of trypsin and leucine aminopeptidase: a proposed mathematical model for IC50 estimation. 767 25

The principal digestive proteinases of the gypsy moth, Lymantria dispar, larval midgut were identified, and the subcellular distribution of the enzyme activities was determined. Proteinase activities of fifth-instar larvae were largely attributed to two luminal serine proteinases, a trypsin-like enzyme (TLE) and an elastase 2-like enzyme (ELA). TLE was purified to homegeneity by benzamidine-Sepharose affinity chromatography. With respect to size (M(r) = 25 kDa), substrate specificity, and interaction with trypsin inhibitors, the gypsy moth enzyme resembled mammalian pancreatic trypsin and trypsin-like enzymes from other insects. Gypsy moth elastase (ELA) was purified from the benzamidine-Sepharose flow-through by mono-Q FPLC. ELA exhibited a slightly smaller size (M(r) = 24 kDa) than TLE. The insect enzyme was inhibited by DFP and chymostatin but was unaffected by TPCK. ELA exhibited little esterolytic activity with BTEE. Succinyl-Ala-Ala-Pro-Leu p-nitroanilide was one of the best substrates for ELA, which is characteristic of elastase 2. TLE and ELA constituted c. 6% of the total soluble protein in midgut lumen of actively feeding fifth-instar larvae. Chymotrypsin and carboxypeptidase activities were not detected in any midgut fraction examined. The brush border membrane (BBM) leucine aminopeptidase (LAP) was isolated from CHAPS-solubilized BBM by FPLC. SDS-PAGE results indicated that the aminopeptidase has an apparent molecular size of c. 100 kDa. The aminopeptidase was inhibited by bestatin and was unaffected by serine proteinase inhibitors.
...
PMID:Gypsy moth midgut proteinases: purification and characterization of luminal trypsin, elastase and the brush border membrane leucine aminopeptidase. 771 46

The survey is devoted to the description of properties of proteolytic enzymes of some sea organisms. Structure peculiarities and properties of proteinases of trypsin and chymotrypsin type, carboxypeptidases A and B, aminopeptidase and leucine aminopeptidase of molluscs, stars, shrimps, fishes and other sea organisms have been considered. Data are presented about trypsins typical of the sea organisms which are characterized by high content of asparaginic and glutaminic acids and small values of activation energy of the reactions which they catalyse. Data are discussed concerning stability of enzymes as to heat denaturation, effect of the environment with external values of pH. Based on the similarity of the substrate specificity of enzymes, their sensitivity to inhibitors, it is concluded that the enzymes of the sea organisms and mammals are similar.
...
PMID:[Peptide hydrolases of marine organisms]. 778 82

The topological disposition of Wolfgram proteins (WP) and their relationship with 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) in human, rat, sheep, bovine, guinea pig and chicken CNS myelin was investigated. Controlled digestion of myelin with trypsin gave a 35KDa protein band (WP-t) when electrophoresed on dodecyl sulfate-polyacrylamide gel in all species. Western blot analysis showed that the WP-t was derived from WP. WP-t was also formed when rat myelin was treated with other proteases such as kallikrein, thermolysin and leucine aminopeptidase. Staining for CNPase activity on nitrocellulose blots showed that WP-t is enzymatically active. Much of the CNPase activity remained with the membrane fraction even after treatment with high concentrations of trypsin when WP were completely hydrolysed and no protein bands with M.W > 14KDa were detected on the gels. Therefore protein fragments of WP with M.W < 14KDa may contain CNPase activity. From these results, it is suggested that the topological disposition of all the various WP is such that a 35KDa fragment is embedded in the lipid bilayer and the remaining fragment exposed at the intraperiod line in the myelin structure which may play a role in the initiation of myelinogenesis.
...
PMID:Topology of Wolfgram proteins and 2', 3'-cyclic nucleotide 3'-phosphodiesterase in CNS myelin: studies with proteases. 782 62

During the last larval stage, corpora allata (CA) of Manduca sexta are inactivated by a factor from the brain. Apparently the same factor (allatinhibin, AI) is secreted by day 4 Vth instar brains kept overnight in Grace's medium. AI is rapidly inactivated by heat or acid but withstands exposure to alkali and can be recovered after freezing and lyophilization. Exposure to pronase, chymotrypsin, carboxypeptidases-A and -Y, as well as leucine aminopeptidase eliminated AI activity completely, whereas after exposure to trypsin and protease XVII-S, some residual activity remained. Inactivation by pyroglutamate aminopeptidase is interpreted as being due to prolinase activity of this enzyme. Incubation of CA with gentamicin, an aminoglycoside antibiotic, affects neither their ability to produce JH in vitro nor their viability in implantation assays. However, AI did not inactivate CA in the presence of low concentrations of gentamicin. This effect was used to guard against false positive assay results possibly produced by allatotoxic contamination. AI was purified by chromatography on Sephadex G-25. All activity recovered emerged from the columns in intermediate fractions with an apparent M(r) of 1,000-2,000.
...
PMID:Partial characterization of allatinhibin, a neurohormone of Manduca sexta. 811 51

An epidemiologic study of Pasteurella haemolytica serovar 1 (Ph1) in market-stressed feeder calves from 7 farms in eastern Tennessee was conducted. The nasal mucus of each calf was cultured sequentially at the farm of origin (day 0), at an auction market (day 133), and at a feedyard in Texas (days 141, 148, 155, and 169). Of the 103 calves tested, 77 were culture-positive, including 1 on day 0, 1 on day 133, 20 on day 141, 57 on day 148, 50 on day 155, and 14 on day 169. From the 143 Ph1 isolates, 20 enzyme profiles were determined by use of a commercial enzyme system that detects 19 enzymatic reactions; 4 antimicrobial susceptibility profiles were obtained, using the disk-diffusion method, which evaluated susceptibility to 11 antibacterial drugs. All isolates were positive for acid phosphatase and alkaline phosphatase, but were negative for alpha-galactosidase, alpha-mannosidase, beta-glucosidase, beta-glucuronidase, cystine aminopeptidase, N-acetyl-beta-glucosaminidase, and trypsin. Other positive enzyme reactions included: leucine aminopeptidase, 140 Ph1 isolates; phosphohydrolase, 90 isolates; alpha-fucosidase, 63 isolates; esterase (C4), 59 isolates; valine aminopeptidase, 30 isolates; esterase lipase (C8), 24 isolates; beta-galactosidase, 2 isolates; and alpha-glucosidase, chymotrypsin and lipase (C14), 1 isolate each. Thirty-four Ph1 profiles were identified, using combined enzyme and antimicrobial susceptibility profiles. The data indicate that the strains isolated during the feedyard period may have been determined more by farm of origin (P < or = 0.001) than by habitation with calves from other farms while in the feedyard.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Identification of Pasteurella haemolytica A1 isolates from market-stressed feeder calves by use of enzyme and antimicrobial susceptibility profiles. 842 78

Incubation of cytosolic extracts of bovine brain with S-adenosyl[methyl-3H]methionine results in the predominant [3H]methyl esterification of a 36-kDa polypeptide. This reaction appears to be distinct from any of the three known types of protein carboxyl methylation reactions previously established. We show here that the methylated 36-kDa polypeptide is a component of a cytosolic protein with a native molecular mass estimated at 178 kDa by gel filtration chromatography. The methyl group is not stable on the protein and is lost as [3H]methanol with a half-life of about 180 min at pH 7.0, 37 degrees C. The methyltransferase responsible for this reaction is a cytosolic protein with a native molecular mass of about 40 kDa that is readily separated from the well described protein-L-isoaspartate (D-aspartate) O-methyltransferase (EC 2.1.1.77). The methyl ester linkage is cleaved by carboxypeptidase Y, suggesting that the 36-kDa polypeptide is methylated on its C-terminal carboxyl group. Extensive digestion of gel-purified 3H-methylated 36-kDa polypeptide with trypsin and leucine aminopeptidase results in a radioactive product that co-chromatographs with authentic L-leucine methyl ester in reverse phase high performance liquid chromatography (HPLC), thin layer chromatography, thin layer electrophoresis, and high resolution-sulfonated polystyrene cation-exchange chromatography. Additionally, the o-phthalaldehyde/beta-mercaptoethanol-derived isoindole derivative of the 3H digestion product co-migrates on HPLC with the corresponding isoindole for L-leucine methyl ester. We demonstrate that a similar methylation system is present in yeast Saccharomyces cerevisiae but not in the bacterium Escherichia coli. These results provide evidence for a new type of reversible posttranslational modification reaction that may function to modulate the activities of its methyl-accepting substrates.
...
PMID:Methyl esterification of C-terminal leucine residues in cytosolic 36-kDa polypeptides of bovine brain. A novel eucaryotic protein carboxyl methylation reaction. 851 74

The tripeptide compounds, Glu-Arg-Pro-amide (ERPm), D-Pro-Thr-Trp-amide (dPTWm) and thioproline-Thr-Trp (tPTW), were obtained by screening of synthetic peptides for growth-inhibitory activity toward cultured transformed cells. The effects of these peptide compounds on proteases were investigated and the results showed that these compounds enhanced the amidolytic activity of serine proteases despite the fact that each reaction was carried out under optimal conditions. ERPm stimulated the activities of trypsin, chymotrypsin, thrombin, plasmin urokinase and elastase. dPTWm also showed similar effects except that toward chymotrypsin. tPTW elevated the activity only of trypsin, chymotrypsin and thrombin. Stimulation of trypsin activity by these compounds was also confirmed by using casein as a substrate. None of these compounds affected the amidolytic activities of metalloproteinases (MMP-1 and MMP-9), cysteine proteinases (m- and mu-calpains, cathepsin B and papain) or an exopeptidase (leucine aminopeptidase). The activation was at least partly due to the stabilization of the catalytic activity of proteases as well as prevention of autolysis.
...
PMID:Enhancement of catalytic activities of serine proteases by tripeptides compounds. 863 1

Feed efficiency in rats fed a low soybean protein isolate (SPI) diet (100 g/kg diet) was dramatically improved with the supplementation of L-methionine (3 g/kg diet). Pancreatic amylase activity was low in rats fed a low SPI diet, and was much higher in the supplemented group than in the non-supplemented group. Pancreatic trypsinogen and chymotrypsinogen contents (as activities of trypsin and chymotrypsin) were not changed with the methionine supplementation. In the small intestine, sucrase and leucine aminopeptidase in the jejunum and ileum were not clearly changed. In conclusion, a small amount of methionine supplemented to a low SPI diet especially induced pancreatic amylase among digestive enzymes. The factor involved in nutritional status, not the physiological action of methionine itself, may contribute the induction of amylase.
...
PMID:Supplementation of methionine to a low soybean protein diet strikingly increases pancreatic amylase activity in rats. 915 Dec 50

The epitope of a monoclonal antibody specific for the alpha 2 isoform of the Na,K-ATPase was determined and its accessibility in native enzyme was examined. Protein fragmentation with N-chlorosuccinimide, formic acid, trypsin, and leucine aminopeptidase indicated binding near the Na,K-ATPase N-terminus but did not unambiguously delineate the extent of the epitope. The ability of the antibody to bind to denatured enzyme made it a good candidate for screening a random peptide library displayed on M13 phage, but the consensus sequence that emerged was not found in the Na,K-ATPase, Full-length cDNA for the Na,K-ATPase was randomly fragmented and cloned into beta-galactosidase to create a lambda gt11 expression library; screening with the antibody yielded a set of overlaps spanning 23 amino acids at the N-terminus. Chimeras of Na,K-ATPase alpha 1 and alpha 2 narrowed down the epitope to 14-19 amino acids. The antibody did not recognize fusion proteins constructed with shorter segments of this epitope. It did recognize a fusion protein containing the M13 library consensus sequence, however, indicating that this sequence, which is rich in proline and hydrophobic amino acids (FPPNFLFPPPP), was a mimotope. The natural epitope, unique to the Na,K-ATPase alpha 2 isoform, was GREYSPAATTAENG. Reconstitution of antibody binding in a foreign context such as M13 PIII protein or beta-galactosidase thus required a relatively large number of amino acids, indicating that antibody mapping approaches must allow for epitopes of significant size. The epitope was accessible in native enzyme and exposed on the cytoplasmic side, documenting the surface exposure of a stretch of amino acids at the N-terminus, where the Na,K-ATPase isoforms differ most.
...
PMID:Epitope and mimotope for an antibody to the Na, K-ATPase. 923 55


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---