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

1. Serum alkaline phosphatase [EC 3.1.3.1] was strongly inactivated by histidine during incubation at pH 8.0 and 45degrees; however, tryptic digestion of the serum strongly protected the enzyme against inactivation by histidine. In the absence of histidine, however, neither heat inactivation of the phosphatase nor the effect of trypsin [EC 3.4.21.4] was observed. Factors affecting the alkaline phosphatase inactivation were studied further. 2. The effect of trypsin on the histidine-induced heat inactivation differed considerably according to the tissue source of the enzyme, which suggests a possible method for distinguishing alkaline phosphatase isoenzymes.
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PMID:Stabilization of human serum alkaline phosphatase to histidine-induced heat inactivation by tryptic digestion. 0 76

The binding of Ca2+ to a salivary phosphoprotein, protein C, was studied by equilibrium dialysis. In 5mM-Tris/HCl buffer, pH 7.5, protein C bound 190 nmol of Ca2+/mg of protein. The apparent dissociation constant, K, was determined to be 1.9 x 10(-4)M and the binding of Ca2+ to the protein was non-co-operative. The binding of Ca2+ to protein C apparently depends on groups which ionize above pH 5.0. Ca2+ binding decreased with increased concentration of the dialysis buffer and on addition of SrCL2, MgCl2 and MnCl2 to the dialysis buffer. Digestion of protein C with trypsin or collagenase or heating of the protein to 60 degrees or 100 degrees C had little or no effect on the Ca2+ binding. Digestion of protein C with alkaline phosphatase caused a decrease in the amount of protein-bound Ca2+. This was also found for another salivary phosphoprotein, protein A. In the absence of Ca2+ the S020,w for protein C was 1.29 S and in the presence of Ca2+ it was 1.46S. Ca2+ may cause a conformational change in the protein or an aggregation of the protein molecules. No conformational changes of protein C in the presence of Ca2+ could be detected by circular dichroism or nuclear magnetic resonance.
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PMID:The binding of calcium to a salivary phosphoprotein, protein C, and comparison with calcium binding to protein A, a related salivary phosphoprotein. 1 96

Amphipathic enzymes, invertase (EC 3.2.1.26), 8-amylase (EC 3.2.1.3), and alkaline phosphatase (EC 3.1.3.1), were purified from the rat small intestinal mucosa as trypsin and Triton forms, the catalytic and regulatory characteristics of which were compared in rats and in drosophila. Differences in the catalytic propertiis of the two enzyme forms were demonstrated, which suggested that the hydrophobic part of the enzyme was involved in maintaining optimal conformation of the catalytic part. Many modifiers have beenfound to influence the Triton rather than the trypsin form of the enzyme. It is therefore suggested that the hydrophobic sub-units of the enzymes might be involved in transmitting information from the cytoplasm into the external surface of the membrane, the cell in this way regulating the activity of surface enzymes. If this is indeed the case, it is suggested that the hydrophobic part performs functions not only of external but also of internal regulation.
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PMID:Catalytic and regulatory properties of the Triton and trypsin forms of the brush border hydrolases. 4 Aug 47

The alkaline phosphatase present on isolated brush border and basal lateral membranes of rat duodenal epithelium were examined by means of a variety of biochemical assays and physical methods. The two alkaline phosphatases have similar pH optima of 9.6--9.8, similar substrate km's for p-nitrophenyl phosphate (PNPP) of 71 micromolar, similar responses to the inhibitors 2-mercaptoethanol, theophylline, phenylalanine, and ethylenediaminetetraacetic acid (EDTA), similar sensitivities to calcium, magnesium, zinc, sodium, and potassium, and similar insensitivities to digestion with trypsin of papain. The two enzymes also exhibit similar molecular weights on SDS-polyacrylamide gels in the range 124,000--150,000, and both enzymes show an Rf value of 0.092 on Triton X-100 polyacrylamide gels, indicating similar intrinsic charges. The Vmax of the brush border enzyme is ten times greater than that of the basal lateral enzyme, 140 mumoles/mg-h as opposed to 14 mumoles/mg-h. The differences in Vmax are a reflection of the known distribution of alkaline phosphatase in rat duodenum, there being more alkaline phosphatase activity present on the brush border than on the basal lateral surface. One other major difference was observed between the two enzymes, the stimulation of the basal lateral and not the brush border alkaline phosphatase by SDS, Triton X-100, or cholate. We conclude that the enzymes are very similar to one another and probably perform similar membrane functions.
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PMID:Alkaline phosphatase of basal lateral and brush border plasma membranes from intestinal epithelium. 4 35

We have perfused isolated rat livers with hypocalcemic (4.4 mg 100 ml) Krebs-Ringer bicarbonate albumin buffer. After 15 min of perfusion, a substance appeared in the perfusate which decreased rat renal adenylate cyclase activation by parathyroid hormone (PTH). The material in the perfusate was purified greater than 50,000-fold by Bio-Gel P-10 chromatography. The purified antagonist decreased the activation of rat renal cortical adenylate cyclase by PTH, glucagon, and epinephrine 75 to 100%. Concentration response curves for each of the hormones indicated a noncompetitive interaction of the inhibitor with the hormone. The inhibition was not species-specific, as the activation of the parathyroid hormone-responsive adenylate cyclase in cat renal cortex was also abolished by the inhibitor from the perfused rat liver. The inhibitor is a peptide, Mr equal to similar to 1000, which is heat-stable, acid-stable, alkai-labile, and is destroyed by trypsin, leucine aminopeptidase, and elastase. It is not destroyed by phosphodiesterase, 5'-nucleotidase, alkaline phosphatase, neuraminidase, RNase, or phospholipase A. The inhibitor is not produced by isolated rat livers perfused with normocalcemic perfusion media. It is unclear whether the peptide is synthesized by the liver or whether it is a breakdown product of a larger peptide or protein in the liver. This is the first reported peptide inhibitor of adenylate cyclase.
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PMID:Isolation of a unique peptide inhibitor of hormone-responsive adenylate cyclase. 16 24

Soluble adenylate cyclase [EC 4.6.1.1] accumulates in the culture medium of exponentially growing Bordetella pertussis (300-900 pmol of cAMP formed/min per ml of 24 hr culture supernatant). In addition, there is an extracytoplasmic adenylate cyclase which enables the intact organisms to form [32P] cAMP (adenosine 3':5'-cyclic monophosphate) from exogenous [alpha-32P] ATP (200-1200 nmol of cAMP formed/min per g wet weight of cells) and which comprises 20-45% of the total adenylate cyclase activity. In contrast, only 1.7 and 2.4% of the total cell malate dehydrogenase [EC 1.1.1.37] and alkaline phosphatase [EC 3.1.3.1], respectively, are detectable in the intact cell. Trypsin treatment of intact organisms destroys 96% of the extracytoplasmic adenylate cyclase, but does not reduce the total cell malate dehydrogenase or a small pool of intracellular adenylate cyclase. Four compartments of adenylate cyclase in B. pertussis are proposed; (A) soluble enzyme in the culture supernatant (up to 20% of the total activity); (B) enzyme associated with intact cells and measurable without cell disruption (20-45%); (C) extracytoplasmic enzyme sensitive to trypsin, but not measurable in intact cells at standard substrate concentrations (40-60%); and (D) intracellular enzyme (7-9%). In comparison with previously studied bacterial adenylate cyclases, the extracytoplasmic location appears to be unique to the B. pertussis enzyme.
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PMID:Extracytoplasmic adenylate cyclase of Bordetella pertussis. 18 May 29

Two metabolically distinct types of bone cell populations were isolated from mouse calvaria by a repetitive digestive procedure with a mixture of collagenase and trypsin. Cells released early in the digestion showed approximately two-fold increases in cAMP when treated with either parathormone or calcitonin. These populations were denoted CT type. Later eluting cells showed larger parathormone-induced increases in cAMP but did not respond to calcitonin. These populations were denoted PT type. Six metabolic and enzymatic activites were measured in the two types of populations: acid and alkaline phosphatases, hyaluronate synthesis, citrate decarboxylation, prolyl hydroxylase, and general protein synthesis. Although each of these activites was present in both cell types, the basal levels of acid phosphatase and hyaluronate synthesis were higher in the CT cells, whereas alkaline phosphatase, citrate decarboxylation, and prolyl hydroxylase were higher in te PT cells. Parathormone stimulated acid phosphatase and hyaluronate synthesis by 100-200% only in the CT cells; in inhibited alkaline phosphatase, citrate decarboxylation, and prolyl hydroxylase by 75-90% only in the PT cells. Calcitonin alone had no effect on any of these activities other than cAMP production, but in inhibited the action of parathormone in the CT cells. The sensitivities, time courses of development,and magnitudes of these hormonal effects were similar to those observed previously in intact calvaria, indicating that the isolated cell system is a reliable model for the study of bone metabolism. Based on the metabolic responses of the cells, we postulate that the CT type of populations is enriched in osteoclasts and, possibly, osteocytes, and the PT type of population is enriched in osteoblasts.
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PMID:Biochemical characterization with parathormone and calcitonin of isolated bone cells: provisional identification of osteoclasts and osteoblasts. 18 58

The content of proteins and nucleic acids and activity of acid and alkaline proteases, RNases, phosphatases and alpha-amylase were studied in the gum and alveolar bone or rats at the age of 1, 3, 6, 12, 18 and 24 months. It is found that a degree of periodontal atrophy strongly and directly correlates with the age of rats. The concentration of DNA and RNA in alveolar bone and of RNA in gum decreases with the age. The hydroxyproline content of periodontal tissues continuously increases till the age of 18th month and then considerably decreases. The activity of trypsin-like proteases, cathepsins and alkaline RNase in periodontal tissues increases reaching the maximum at the age of 6-18 months, and the activity of alkaline phosphatase decreases in the process of aging.
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PMID:[Biochemical properties of aging of rat periodontium]. 20 87

The effect of 1.8 mg/liter (LC50) of mercuric chloride exposure on the activities of alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, amylase, pepsin, trypsin, tripeptidase glycyl-glycine dipeptidase and carnosinase has been examined in Channa punctatus. The three phosphatases have been inhibited in the liver but showed an increase in activity in the intestine and pyloric caeca. Amylase, pepsin and trypsin have also shown a slight increase in activity. There has been no significant alteration in the activites of the peptidases. The results show that mercury inhibits the activites of phosphatases in the liver but has no significant effect on the digestive enzymes within the experimental period of 96 hours.
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PMID:Effect of mercuric chloride on the digestive system of a teleost fish, Channa punctatus. 21 48

Alterations in the activities of alkaline phosphatase, acid phosphatase, glucose-6-phosphatase amylase, trypsin, pepsin, aminotripeptidase, glycylglycine dipeptidase and carnosinase due to exposure of Channa punctatus to a sublethal concentration (0.30 mg/L) of mercuric chloride by bath for 20 days have been studied in the different parts of the digestive system. Afall in the activities of the three phosphatases was recorded except for alkaline phosphatase which showed a slight elevation in activity in intestine and pyloric caeca. An increase in the activity of amylase and the two proteases was observed in all the portions of the digestive system. The three peptidases revealed a decrease in activity.
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PMID:The in vivo effect of mercuric chloride on some digestive enzymes of a fresh water teleost fish, Channa punctatus. 22 1


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