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

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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)

The role played by the gut juice of insects in the infective process of insect viruses was examined. Analysis of larval gut extract of Heliothis armigera by SDS-PAGE revealed protease activity associated with components of molecular weights 48,000 and 94,000. Proteases were found to be associated with occlusion bodies and virions of both nuclear polyhedrosis virus (NPV) and cytoplasmic polyhedrosis virus (CPV) infecting H. armigera. CPV occlusion bodies were dissolved by gut juice extract at pH 8.0, trypsin and chymotrypsin at pH 8.0, and carbonate-chloride solution at pH 10.5. Trypsin treatment was selective for occlusion bodies of CPV at pH 8.0, whereas solutions more alkaline than pH 10.0 without added enzymes were adequate to digest NPV occlusion bodies. This property was used to identify and separate the two types of viruses from a mixed infection. Gut extract proteases have characteristics similar to those of trypsin.
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PMID:Midgut and viral associated proteases of Heliothis armigera. 633 72

To test the discriminatory potential of certain indices of pancreatic function we performed duodenal perfusion studies and measured trypsin, bicarbonate, and lactoferrin outputs, and plasma concentrations of pancreatic polypeptide and motilin in the basal state and during continuous intravenous stimulation with 100 ng kg-1h-1 Ceruletide and 1 CU kg-1h-1 secretin. The following groups were studied: 12 normal volunteers (NV), seven patients with chronic pancreatitis with steatorrhea (CPS), and seven without steatorrhea (CP). Stimulated trypsin outputs, after 45 min of stimulation, were the best discriminant among the groups (NV versus CPS, p less than 0.0005; NV versus CP, p less than 0.005; CP versus CPS, p less than 0.05). Basal trypsin outputs showed similar patterns but failed to discriminate between NV and CP. Bicarbonate outputs were less discriminatory than trypsin outputs. Lactoferrin outputs failed to discriminate, but transient high peak outputs occurred in the initial stimulation period in all four patients with calcific chronic pancreatitis, suggesting a washout phenomenon. Basal motilin levels were elevated in both groups of pancreatitis (p less than 0.05). Stimulated pancreatic polypeptide levels were lower in CPS (NV versus CPS, p less than 0.05) but higher in CP (NV versus CP, p less than 0.005). These differences were also apparent in the basal state. We conclude that the best discrimination among the three groups was achieved by measurement of trypsin outputs, after 45 min of stimulation. In addition, the pancreatic polypeptide response may be used as a marker of residual pancreatic function in chronic pancreatitis.
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PMID:Pancreatic exocrine and endocrine responses in chronic pancreatitis. 636 35

The paper deals with the effect of changes in the concentration of carbonic acid in the medium on the reaction rate catalyzed with enzymes of various spectrum of the action. It is shown that the presence of carbonic acid in the medium reaction increases the rate of reactions catalyzed with lactate dehydrogenase of the rabbit liver soluble fraction, with glucose-6-phosphate dehydrogenase from yeast and trypsin. Under the same conditions the reaction rate catalyzed with glucose-6-phosphate dehydrogenase of the rabbit liver soluble fraction and with ATP-citrate (pro-3S)-lyase is considerably decreased. Changes in the carbonic acid concentrations within the physiological limits are found to have no effect on lactate dehydrogenase from the cattle heart and chymotrypsin.
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PMID:[Effect of HCO3- and carbon dioxide at various concentrations on activity of certain enzymes]. 677 May 15

Platelets are able to stimulate an increase in two distinct activities, tissue factor (thromboplastin) and fibrinolytic inhibition, in human fibroblasts in vitro. A procedure has been developed which allows the purification of a platelet macromolecule which is able to stimulate both of these changes. Washed human platelets were homogenized, sonicated, and then centrifuged at 90,000 x g for 2 h. The resulting pellet was solubilized in 0.05 M sodium carbonate, pH 10.5, and chromatographed on Sephadex G-200, then on hydroxylapatite, resulting in a 135-fold purification and a 20% yield. When the purified material was further fractionated on sodium dodecyl sulfate-polyacrylamide gels, stimulatory activity for both tissue factor and fibrinolytic inhibition was found only in the 75,000-dalton region. The active material could be inactivated by mercaptoethanol with no change in its apparent molecular weight. It was readily inactivated by trypsin with the concomitant loss of the 75,000-dalton Coomassie-staining band. Assay of the purified material for carbohydrate was negative. After isoelectric focusing, the purified material had a major band at pH 5.8 which stimulated both tissue factor and fibrinolytic inhibition. Subcellular fractionation of platelet homogenates by sucrose density gradient centrifugation resulted in a 2-fold increase in stimulatory material in the granule/mitochondrial fraction. This platelet-derived protein may represent a physiologically important regulator for both cellular procoagulant and the net fibrinolytic activity of systemic cells.
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PMID:Purification of a platelet protein which stimulates fibrinolytic inhibition and tissue factor in human fibroblasts. 711 21

The interaction between bovine lactoferrin (bLf) and ascorbate (Asc) was investigated through malondialdehyde (MAD) formation in a solution containing DNA, bleomycin (BLM), and Fe2+ or Asc. The inhibition by bLf on MDA formation in the presence of Asc was not changed even by adding carbonate or oxalate ions to the solution. The percentage inhibition by the hydrolysates of bLf treated with pepsin, trypsin, and both enzymes on MDA formation was almost the same as that by the untreated bLf in the presence of Asc. The inhibition of MDA formation also occurred with the filtrate obtained from a solution containing bLf and Asc, but not with that from a solution of bovine serum albumin and Asc. The interaction of bLf and Asc was observed by gel filtration in a Sephadex G75 column. The binding amount of Asc was estimated to be 87 mol per mole of bLf.
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PMID:Interaction of lactoferrin with ascorbate and the relationship with bleomycin-dependent DNA damage. 753 54

The paper presents results of scientific activity of the Department of Metabolism Regulation. The main sections are: carbamates formation and their role in metabolism regulation; metabolic system of acid-base homeostasis in animals; polyamines metabolism in the extremal states; mechanisms of metabolic adaptation in mammals. Experimental data are presented which evidence for the fact that tissue proteins in vivo are subjected to nonenzymic carboxylation with formation of carbominic groups. In this case a charge variation in definite sites of protein molecule is observed, which specifies variation of the protein conformation and biological properties. Basic regularities of protein carbamate formation reactions are revealed with factors affecting their intensity. It is shown that the presence of carbonic acid in the medium increases the rate of reactions catalyzed with lactate dehydrogenase from the rabbit liver, glucose-6-phosphate dehydrogenase from yeast and trypsin. Under the same conditions the reaction velocity rate catalyzed with glucose-6-phosphate dehydrogenase from the rabbit liver and with ATP-citrate (pro-35)-liase is considerably decreased. Changes in the concentration of carbonic acid within the physiological limits are found to have no effect on lactate dehydrogenase from the cattle heart and chymotrypsin. The rate of the reaction catalyzed by NAD-dependent malate denydrogenase was studied as affected by carbon dioxide. It is shown that acceleration of the catalysis in these systems depends on the presence of both a bicarbonate anion and soluble carbon dioxide. IR spectra of NAD-dependent malate dehydrogenase in the deuterium oxide solutions were studied in the CO2-free solutions and solutions saturated with it.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Role of low molecular weight metabolites as natural regulators of metabolism]. 757 Oct 78

The activity of the Na-H antiporter is inhibited by cyclic AMP-dependent protein kinase A (cAMP-PKA). The inhibitory effect of PKA on the Na-H antiporter is mediated through a regulatory protein that can be dissociated from the antiporter by limited protein digestion. PKA also inhibits the activity of the Na+/HCO3- cotransporter. We investigated whether the activity of Na+/HCO3- cotransporter and the effect of PKA on this transporter may also be regulated by limited protein digestion. In rabbit renal cortical basolateral membranes (BLM) and in solubilized BLM reconstituted in liposomes (proteoliposomes), trypsin (100 micrograms) increased 22Na uptake in the presence of HCO3 but not in the presence of gluconate, indicating that trypsin does not alter diffusive 22Na uptake but directly stimulates the Na+/HCO3- cotransporter activity. In proteoliposomes phosphorylated with ATP, the catalytic subunit (CSU) of cAMP-PKA decreased the activity of the Na+/HCO3- cotransporter (expressed as nanomoles/mg protein/3s) from 23 +/- 10 to 14 +/- 6 (P < 0.01). In the presence of trypsin, the inhibitory effect of CSU of cAMP-PKA on the activity of Na+/HCO3- cotransporter was blunted. To identify a fraction that was responsible for the inhibitory effect of the CSU on the Na+/HCO3- cotransporter activity, solubilized proteins were separated by size exclusion chromatography. The effect of CSU of cAMP-PKA on the Na+/HCO3- cotransporter activity was assayed in proteoliposomes digested with trypsin with the addition of a fraction containing the 42 kDa protein (fraction S+) or without the 42 kDa protein (fraction S-).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Renal cortical basolateral Na+/HCO3- cotransporter. III. Evidence for a regulatory protein in the inhibitory effect of protein kinase A. 763 86

Rabbit neutral endopeptidase 24.11 (NEP) is a type II membrane protein with a positively charged 27 amino acid residue NH2-terminal cytoplasmic domain, a 20 amino acid residue hydrophobic signal peptide/membrane anchor domain, and a large catalytic COOH-terminal domain exposed on the exoplasmic side of the membrane. To study the role of the cytosolic domain in anchoring NEP in the plasma membrane, we constructed two mutants in which this cytosolic domain was deleted. In the first mutant (NEP delta cyto), a Glu residue was present in NH2-terminus, while a Lys residue was substituted at the same position in the second mutant (NEP delta cyto(K)). To better understand the interaction of these mutants with the rough endoplasmic reticulum membrane, the mutated NEP cDNAs were transcribed and translated in vitro in the presence of microsomal membranes. Our studies showed that deletion of the hydrophillic cytosolic domain affects translocation of the NEP polypeptide chain. Substitution of a positively charged Lys residue for the Glu residue at the NH2-terminus of the deletion mutant only partly restored translocation of the polypeptide chain. Furthermore, carbonate extraction and trypsin digestion of the microsomal membranes indicated that the deletion mutants are inserted in the microsomal membranes as type III membrane proteins with their COOH-terminal domain exposed on the exterior of the microsomes. Thus, efficient translocation is dependent on the presence of a charged cytoplasmic domain.
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PMID:Translocation of neutral endopeptidase 24.11 mutants with deletions of the NH2-terminal cytosolic domain. 784 Sep 37

We investigated the effect of intraduodenal administration of oligopeptide and a mixed amino acid solution, which contains the same amino acid composition as oligopeptide, on pancreatic exocrine secretion and the release of secretin and cholecystokinin (CCK). Anesthetized rats were prepared with pyloric ligation and cannulation of pancreatic duct and bile duct. Protein derivatives in three different doses (oligopeptide: 25, 100, and 400 mg/h; and mixed amino acid solution: 70, 140, and 280 mg/h, pH 7.0) were infused into the duodenum for 1 h. Pancreatic juice was collected, and plasma concentrations of secretin and CCK were measured by radioimmunoassay. In addition, the effect of intravenous injection of an antisecretin serum or a CCK antagonist, loxiglumide, on pancreatic secretion stimulated by oligopeptide or mixed amino acid solution was also studied. Oligopeptide produced a significant dose-related increase in pancreatic secretion including volume, HCO3-, amylase, and trypsin output, plasma secretin (r = 0.792, P < 0.001), and plasma CCK (r = 0.421, P < 0.01). Similarly, mixed amino acid solution produced a dose-related increase in pancreatic juice volume, HCO3-, amylase, and trypsin output. Compared with CCK, the percentage increase in plasma secretin was 7.3x and 2.8x higher in response to oligopeptide (400 mg/h) and mixed amino acid solution (280 mg/h), respectively. An antisecretin serum almost completely inhibited volume flow and HCO3- output stimulated by oligopeptide as well as mixed amino acid solution, but not amylase and trypsin output. In contrast, loxiglumide significantly suppressed amylase and trypsin output stimulated by protein derivatives, but did not affect volume flow or HCO3- output.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of protein derivatives on pancreatic secretion and release of secretin and CCK in rats. 794 15

Nodulin-24 is a nodule-specific protein of the peribacteroid membrane (PBM) in soybean. It has an apparent molecular mass of 33 kDa while its full-length cDNA encodes a polypeptide of only 24 kDa. In vitro transcription of nodulin-24 cDNA followed by translation resulted in a peptide translocated into microsomal membranes with cleavage of a signal sequence. The cleavage site of the signal sequence in nodulin-24 was determined to be between Ala (A25) and Arg (R26) by microsequencing of the [3H]leucine-labeled processed peptide. Fusion of the signal sequence of nodulin-24 with the beta-glucuronidase peptide prevented co-translational cleavage of the signal sequence although the translocation of the fused protein into microsomes occurred co-translationally. Trypsin treatment of membrane-translocated nodulin-24 did not result in any alteration in size suggesting that the newly synthesized peptide is fully protected in the membrane vesicle. Fusion of nodulin-24 with beta-glucuronidase also showed no change in size following trypsin treatment, suggesting that nodulin-24 has no membrane-spanning region. In addition, in vitro synthesized nodulin-24 was present in the supernatant fraction after sonication of microsomal membranes. Mature nodulin-24, on the other hand, is not solubilized from PBM by sodium carbonate (pH 11) or EGTA and is soluble only in detergent. These data suggest that nodulin-24 is synthesized as a lumenal protein in the endoplasmic reticulum and post-translationally attached to the membranes en route to the PBM. This processing results in a significant increase in the apparent molecular mass of nodulin-24 which may be due to the attachment of membrane lipids as this protein shares characteristics with membrane lipoproteins of many pathogenic bacteria.
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PMID:Nodulin-24 follows a novel pathway for integration into the peribacteroid membrane in soybean root nodules. 812 12


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