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 venom of V. cincta contains acetylcholine (ACh), histamine and 5-hydroxytryptamine (5-HT). Blockers of these agonists did not block completely the hypotensive and smooth muscle contractile activity of venom. On smooth muscle, there was a residual slow contraction. The active substance which produced this slow contraction was separated by solvent extraction, gel filtration and TLC. The purified material (which has been provisionally designated "Vecikinin") lowered cat, rat and guinea pig blood pressure, increased amplitude of cardiac contraction, and increased capillary permeability. Vecikinin contracted several smooth muscle preparations (rat uterus, rat ascending colon, guinea pig ileum, guinea pig colon and rat ileum), while relaxing rat duodenum. Its contractile activity was not lost on boiling, but acid or alkali-boiling reduced its contractile activity. It was inactivated on incubation with chymotrypsin and carboxypeptidase but not with trypsin, pepsin or leucine aminopeptidase. It is a peptide, appears to be of low molecular weight, and could be distinguished from substance P, angiotensin, bradykinin and hornet or wasp kinin.
...
PMID:Isolation, partial purification and pharmacodynamics of a slow contractile substance in the venom sac extract of the wasp Vespa cincta Fabr. 240 29

Hydrolytic enzymes were measured in gut contents from four sudden death victims. Pancreatic amylase and total protease activities decreased distally from the small bowel to the sigmoid/rectum region of the large intestine, showing that considerable breakdown or inactivation of the enzymes occurred during gut transit. To determine whether pancreatic enzymes were substrates for the gut microflora, mixed populations of bacteria were grown in a 3-stage continuous culture system on a medium that contained pancreatic extract as the sole nitrogen source. The multichamber system (MCS) was designed to reproduce in vitro, the low pH, high nutrient, fast growth conditions of the caecum and right colon and the neutral pH, low nutrient, slow growth conditions of the left colon. Results showed that pancreatic amylase was resistant to breakdown by intestinal bacteria compared with the peptide hydrolases in pancreatic secretions. Leucine aminopeptidase, trypsin and to a lesser degree, chymotrypsin, were easily degraded by gut bacteria, but pancreatic elastase was comparatively resistant to breakdown. Protein degradation in the MCS, as determined by enzyme activities, protein concentration and ammonia and phenol production, increased concomitantly with system retention time over the range 24-69 h. These results suggest that intestinal bacteria play an important role in the breakdown of hydrolytic enzymes secreted by the pancreas and that this process and protein fermentation in general, is likely to occur maximally in individuals with extended colonic retention times.
...
PMID:Influence of retention time on degradation of pancreatic enzymes by human colonic bacteria grown in a 3-stage continuous culture system. 248 Mar 41

N-alpha-[(S)-1-carboxy-3-phenylpropyl]-L-lysyl-L-proline (MK-0521) is a new non-sulfhydryl-containing angiotensin converting enzyme (ACE) inhibitor. The present investigation describes its ACE and other enzymes inhibitory properties and compares it to those of captopril, MK-421 and MK-422 in vitro. MK-0521 inhibited rat pulmonary ACE by 50% (IC50) at a concentration of 3 nM and was 6.13 times more potent than captopril. The IC50 values of MK-421 and MK-422 against ACE were 2,000 nM and 3.5 nM, respectively. MK-0521 had practically no inhibitory activities against carboxypeptidase A, carboxypeptidase B, leucine aminopeptidase, papain, pepsin and trypsin. The kinetic study on the inhibitory activity of M-0521 against ACE using Lineweaver-Burk plots indicated that MK-0521 exerted competitive ACE inhibition. The dialysis study conducted on the ACE-MK-0521 complex revealed that the inhibitory effect of MK-0521 against ACE was reversible. In the guinea pig ileum, MK-0521 potentiated the contractile effect of bradykinin and depressed the contractile effect of angiotensin I. These effects on bradykinin and angiotensin I were 33.11 and 2.63 times more potent than that of captopril, respectively. The present results suggest that MK-0521 may show a potent hypotensive effect in vivo.
...
PMID:[Inhibitory effect of N-alpha-[(S)-1-carboxy-3-phenylpropyl]-L-lysyl-L-proline (MK-0521) on angiotensin converting enzyme in vitro]. 254 78

Gastrin-17 induces hypocalcemia in the rat without stimulating calcitonin release. The gastrin-induced hypocalcemia persisted after thyroparathyroidectomy or parathyroidectomy. In contrast, gastrectomy or extirpation of the acid-producing part of the stomach prevented the hypocalcemic effect, suggesting the involvement of the proximal stomach in the gastrin-evoked lowering of blood calcium. The drop in blood calcium upon injection of gastrin-17 did not reflect a loss of calcium via the gastric juice or via the urine. Extracts of the acid-producing mucosa of the rat stomach had a hypocalcemic effect. The extracts were purified by gel chromatography and reversed-phase high-performance liquid chromatography. Digestion with leucine aminopeptidase destroyed the hypocalcemic activity, while trypsin had no effect, suggesting a peptide (or peptides) with an unprotected NH2 terminus and without basic amino acid residues (or with protected basic amino acids). Both gastrin-17 and the mucosal extract stimulated the uptake of 45Ca into bone (radius and sternum). Gastrin-17 was without effect in rats that had undergone gastrectomy, while the mucosal extract was equally effective in gastrectomized and unoperated rats. We suggest that the effects of gastrin-17 on blood calcium and on calcium transfer into bone are indirect and that gastrin-17 stimulates the release of a peptide hormone, tentatively named gastrocalcin, from the acid-producing mucosa of the stomach. Gastrocalcin stimulates the uptake of 45Ca into bone, thereby causing hypocalcemia.
...
PMID:Gastrin releases a blood calcium-lowering peptide from the acid-producing part of the rat stomach. 270 48

Human placental aminopeptidase A (AAP) was purified 3,900-fold from human placenta and characterized. The enzyme was solubilized from membrane fractions with Triton X-100, then subjected to trypsin digestion, zinc sulfate fractionation, chromatographies with DE-52, Sephacryl S-300, and hydroxylapatite, affinity chromatography with Bestatin-Sepharose 4B, and finally immunoaffinity chromatography with the antibody against microsomal leucine aminopeptidase (LAP). Aminopeptidase A was completely separated from leucine aminopeptidase by the immunoaffinity chromatography. The apparent relative molecular mass (Mr) of the enzyme was estimated to be 280,000 by gel filtration. The purified enzyme was most active at pH 7.1 with L-aspartyl-beta-naphthylamide (L-Asp-NA) as substrate; the Km value for this substrate was 4.0 mmol/l in the presence of Ca2+. Human placental aminopeptidase A was markedly activated by alkaline earth metals (Ca2+, Sr2+, Ba2+), but strongly inhibited by metal chelating agents such as EDTA and o-phenanthroline. The highest activity was observed with L-glutamyl-beta-naphthylamide, while only minimal hydrolysis was found with some neutral and basic amino acid beta-naphthylamides.
...
PMID:Purification and characterization of human placental aminopeptidase A. 285 46

The suitability of eleven 4-alkylidene oxazolones for the determination of four hydrolases, alpha-chymotrypsin, trypsin, carboxylesterase and leucine aminopeptidase, was tested. The specific activities were in general low compared with those obtained with the classical substrates but the Kmapp values were also small. Hence, the kcat/Kmapp ratios of the oxazolones, the optimal indicator of activity, remained in the usual range. The high differential absorption coefficients of the oxazolones in the UV range render these substrates very suitable for the determination of active site normalities if the solubilities of the acyl enzymes and the magnitudes of the rapid bursts are sufficient. Since some of the oxazolones fluoresce, the sensitivity of the method may be increased up to 1000 x by fluorescence detection. The titrations may be carried out in organic solvents, e.g. dimethyl sulphoxide, which greatly stabilize the hydrolases. The high specificity of the oxazolones permits active site titrations in the presence of other hydrolases.
...
PMID:4-alkylidene oxazolones as substrates and inhibitors for sensitive assays of the normality of active sites and the catalytic properties of hydrolases. 291 72

The digestive tracts of adult and juvenile Dover sole were examined for protease activities. A pepsin-like protease with an optimal pH value of 1.7 predominated in the stomach region, but the main endoprotease action in the foregut, midgut and hindgut regions was optimal in the range of pH 9.5-10.5 and showed good activity towards elastin orcein. Experiments using synthetic substrates suggested the presence of chymotrypsin- and trypsin-like activities optimal between pH 7 and 8. Collagenase activity was also shown to exist in this pH region. The presence of enzymes corresponding to carboxypeptidases a and b and leucine aminopeptidase was indicated. The possible significance of these results to the farming of Dover sole is discussed.
...
PMID:Metabolism in marine flatfish. II. Protein digestion in Dover sole (Solea solea L.). 299 Aug 7

An inhibitor of sodium-potassium-ATPase has been partially purified from the culture medium obtained from hypothalamic cells maintained in a capillary membrane perfusion system, and some of the properties of this inhibitory factor have been investigated. Gel filtration (Sephadex G-25 Superfine) of heat-treated medium (80 degrees C for 10 min) resulted in elution of inhibitory activity in the post-salt fraction. These fractions inhibited active (i.e. sodium-potassium-ATPase-mediated) sodium transport in intact human erythrocytes, displaced [3H]ouabain from its binding site, and directly inhibited canine kidney sodium-potassium-ATPase as measured by NADH oxidation. High-performance liquid chromatography (on Hypersil ODS) of these fractions after desalting yielded one region which showed inhibitory activity on all three assays. Inhibition of sodium-potassium-ATPase was dose-related and filtered through an Amicon UM10 membrane. Incubation of this material with dispase, carboxypeptidase A, chymotrypsin, and prolidase destroyed inhibitory activity, whereas trypsin and leucine aminopeptidase were ineffective. These studies show that hypothalamic neurones release a low molecular weight heat-stable peptide which inhibits active sodium transport, ouabain binding, and sodium-potassium-ATPase.
...
PMID:Characterization and partial purification of the sodium-potassium-ATPase inhibitor released from cultured rat hypothalamic cells. 299 73

Effects of condensed tannins isolated from Rhei Rhizoma on the activities of angiotensin converting enzyme (ACE) and various proteases were examined in vitro. Among the various condensed tannins tested, procyanidin B-5 3,3'-di-O-gallate and procyanidin C-1 3,3',3"-tri-O-gallate strongly inhibited the activity of ACE. The concentration of procyanidin B-5 3,3'-di-O-gallate required for 50% inhibition of ACE was 1.3 X 10(-6) M. The inhibition of ACE by condensed tannins was reversible and non-competitive, according to dialysis and to Dixon plots. However, over one hundred times the concentration was required to inhibit activities of other proteases such as trypsin, chymotrypsin, leucine aminopeptidase, carboxypeptidase A and urinary kallikrein. These results suggest that the inhibitory effects of condensed tannins on the activities of ACE are specific.
...
PMID:Inhibitory effects of condensed tannins on angiotensin converting enzyme. 303 68

A novel inhibitor of angiotensin I converting enzyme (ACE), designated K-13, was isolated from the culture broth of Micromonospora halophytica subsp. exilisia K-13. K-13 inhibited ACE non-competitively when hippuryl-L-histidyl-L-leucine was used as a substrate. The inhibition constant (Ki) was 0.349 microM. K-13 hardly inhibited carboxypeptidase A, trypsin, alpha-chymotrypsin, leucine aminopeptidase, and aminopeptidase B even at a level of 61 microM. When K-13 was administered intravenously to rats, it inhibited the pressor response to angiotensin I.
...
PMID:K-13, a novel inhibitor of angiotensin I converting enzyme produced by Micromonospora halophytica subsp. exilisia. I. Fermentation, isolation and biological properties. 303 44


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

---