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)

Six pigs, initially of 35 kg mean live weight, were each fitted with a re-entrant cannula. This was formed on either side of a short pouch of duodenum into which the pancreatic duct opened and which contained a simple cannula linked to the centre of the re-entrant cannula. Each pig received two diets: diet A was based on wheat starch, sucrose and casein, while diet B was based on barley and soya-bean meal. The diets were given in equal amounts at 12 h intervals. Digesta and pancreatic juice were collected continuously during three 12 h periods for each pig on each diet. Mean duodenal output: dietary intake values for diets A and B respectively were: digesta 1.80, 2.86; dry matter 1.05, 1.03; nitrogen 1.05, 1.06; trichloroacetic acid (TCA)-soluble N 7.69, 9.10; glucose 0.97, 0.89. For diet A the proportion of TCA-soluble N in total N rose from 13 to 50% during 12 h, while it was approximately 50% throughout 12 h for diet B. Mean total pepsin (EC 3.4.23.1) activities (units/24 h) were 760449 (diet A) and 1 466 571 (diet B). Salivary and gastric secretions were calculated to be approximately 4 and 8 kg/24 h for diets A and B respectively. Mean flows in pancreatic juice (g/24 h) for diets A and B respectively were: juice 1204, 2182; protein 10.94, 12.10; N 1.98, 2.14; ash 9.46, 17.31; sodium 3.88, 6.91; potassium 0.23, 0.54; calcium 0.031, 0.046; phosphorus 0.024, 0.026. Mean total enzyme activities (units x 10(-3)/24 h) for diets A and B respectively were: trypsin (EC 3.4.21.4) 138, 114; chymotrypsin (EC 3.4.21.1) 84, 84; carboxypeptidase A (EC 3.4.2.1) 5, 4; carboxypeptidase B (EC 3.4.2.2) 15, 17; amylase (EC 3.2.1.1) 1061, 981. It was calculated that the minimum amount of endogenous N from saliva and gastric secretion was 0.3-0.6 g in 24 h. This assumes no absorption of N occurred anterior to the duodenal cannula.
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PMID:Studies on gastric digestion of protein and carbohydrate, gastric secretion and exocrine pancreatic secretion in the growing pig. 640 23

The trypsin inhibitor TI-2 produced by Streptomyces griseus Cal in a medium, containing beef extract and peptone as the nitrogen source, was purified by ammonium sulfate precipitation and gel filtration. Amino acid analysis showed that it contained hydroxyproline and carbohydrate whereas tyrosine, tryptophan, and cystine were absent. The composition of the inhibitor protein thus showed a similarity to collagen. Growth of the organism in a medium with gelatin as the sole nitrogen source resulted in the production of the same TI-2 inhibitor. Incubation of gelatin with either concentrated culture filtrate, trypsin, or chymotrypsin also yielded trypsin inhibitors. The product isolated from the in vitro incubation of gelatin with trypsin appeared to be the same as TI-2. To the author's knowledge, this is the first report that peptides obtained by enzymic hydrolyses of gelatin are trypsin inhibitors.
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PMID:Studies on TI-2 trypsin inhibitor of Streptomyces griseus. 642 69

A protein-free diet is often used in animal experimentation to estimate the amount of total endogenous nitrogen secreted by the organism. To test the validity of this technique, we carried out a study on pigs describing the short-term (8-day) effect of a protein-free diet on exocrine pancreas nitrogen secretion; this nitrogen was considered as representative of total endogenous nitrogen. After 11 pigs had been adapted to a balanced diet (14% protein), they were chronically fistulated in the pancreatic duct and duodenum. Pancreatic secretion and its various parameters (volume, total protein and chymotrypsin, trypsin, amylase and lipase activities) were measured over a first experimental period of 4 days, during which the pigs continued to receive the balanced diet, and over a second experimental period of 8 days during which they were given a protein-free diet. The results show that the amount of pancreatic protein did not change during the period the protein-free diet was given. After 2 days, chymotrypsin specific activity dropped, while amylase and lipase specific activities decreased little and slowly after 6 days. However, for short-term experiments, the protein-free diet proved to be an adequate technique for determining the production of total endogenous nitrogen in the digestion tract.
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PMID:[Effect of a short-term protein-free diet on endogenous nitrogen secretion: exocrine pancreas secretion in the pig]. 648 7

A rice bran protein concentrate (RBPC) was prepared from de-fatted rice bran by extraction with a 1% sodium chloride solution and by acetone-precipitation. This protein concentrate contained 45% protein, which was as good as casein in terms of protein quality being judged from the results of amino acid analysis. On the other hand, RBPC possessed the trypsin inhibitor activity corresponding to the complete inhibition of about 6 mg of bovine trypsin per 1 g of dry material. The activity was, however, completely destroyed by autoclaving RBPC for 30 min at 121 degrees C. In vitro digestion tests showed that RBPC was easily digested by pepsin but was resistant to the attack by trypsin, compared with autoclaved RBPC. Concerning in vivo digestion, however, there was no significant difference in apparent nitrogen digestibility between RBPC and the heated RBPC. In growth experiments with weanling rats fed a 10% level of protein diet, growth depression and the tendency of slight pancreatic hypertrophy were observed in rats receiving a RBPC diet. It is presumed that one of the reasons which explains these phenomena is the presence of trypsin inhibitor in RBPC.
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PMID:Nutritional significance of a rice bran concentrate with trypsin inhibitor activity. 661 92

A cytochrome b5-like hemoprotein associated with the outer membrane of rat liver mitochondria, OM cytochrome b, was purified to homogeneity after solubilization with trypsin. OM cytochrome b was separated from microsomal cytochrome b5 by hydroxylapatite chromatography, though they were indistinguishable in DEAE-cellulose chromatography and in Sephadex G-75 gel filtration. The absorption spectra of reduced OM cytochrome b and cytochrome b5 in the visible region at liquid nitrogen temperature showed small but significant differences between them. A clear difference was also detected in amino acid composition, particularly in the contents of basic amino acids and methionine. Using rabbit antibodies prepared against purified OM cytochrome b and cytochrome b5, immunochemical comparison was also carried out. No immunological cross reaction was observed by Ouchterlony double diffusion in agar gel or in a quantitative immunoprecipitation test. It is thus concluded that OM cytochrome b is distinct from microsomal cytochrome b5.
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PMID:Cytochrome b5-like hemoprotein of outer mitochondrial membrane; OM cytochrome b. I. Purification of OM cytochrome b from rat liver mitochondria and comparison of its molecular properties with those of cytochrome b5. 676 29

UDP-galactose: N-acetylglucosamine galactosyltransferase (GT) and CMP-sialic:desialylated transferrin sialyltransferse (ST) activities of rat liver Golgi apparatus are membrane-bound enzymes that can be released by treatment with Triton X-100. When protein substrates are used to assay these enzymes in freshly prepared Golgi vesicles, both activities are enhanced about eightfold by the addition of Triton X-100. When small molecular weight substrates are used, however, both activities are only enhanced about twofold by the addition of detergent. The enzymes remain inaccessible to large protein substrates even after freezing and storage of the Golgi preparation for 2 mo in liquid nitrogen. Accessibility to small molecular and weight substrates increases significantly after such storage. GT and ST activities in Golgi vesicles are not destroyed by treatment with trypsin, but are destroyed by this treatment if the vesicles are first disrupted with Triton X-100. Treatment of Golgi vesicles with low levels of filipin, a polyene antibiotic known to complex with cholesterol in biological membranes, also results in enhanced trypsin susceptibility of both glycosyltransferases. Maximum destruction of the glycosyltransferase activities by trypsin is obtained at filipin to total cholesterol weight ratios of approximately 1.6 or molar ratios of approximately 1. This level of filipin does not solubilize the enzymes but causes both puckering of Golgi membranes visible by electron microscopy and disruption of the Golgi vesicles as measured by release of serum albumin. When isolated Golgi apparatus is fixed with glutaraldehyde to maintain the three-dimensional orientation of cisternae and secretory vesicles, and then treated with filipin, cisternal membranes on both cis and trans faces of the apparatus as well as secretory granule membranes appear to be affected about equally. These results indicate that liver Golgi vesicles as isolated are largely oriented with GT and ST on the luminal side of the membranes, which corresponds to the cisternal compartment of the Golgi apparatus in the hepatocyte. Cholesterol is an integral part of the membrane of the Golgi apparatus and its distribution throughout the apparatus is similar to that of both transferases.
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PMID:Orientation of glycoprotein galactosyltransferase and sialyltransferase enzymes in vesicles derived from rat liver Golgi apparatus. 678 76

The time-course of proteolysis of casein and gluten by pancreatic enzymes (trypsin, chymotrypsin, pancreatic juice) was studied in vitro with various concentrations of enzyme or substrate. The effect of a previous peptic proteolysis, with or without sodium phytate, on proteolysis by pancreatic juice was also studied. Proteolysis was evaluated by measuring the nitrogen in products solubilized in trichloroacetic acid (peptides + amino acids) and in phosphotungstic acid (amino acids). Without a previous peptic proteolysis, at a low enzyme/substrate ratio, the release of peptides and amino acids was greater for casein than for gluten. At a high enzyme/substrate ratio, peptide release by pancreatic juice and chymotrypsin was quite similar for casein and gluten but amino acid release was a little less for gluten. After a previous high peptic proteolysis without sodium phytate, pancreatic juice proteolysis, at a low enzyme/substrate ratio, was increased. Peptide release was similar for casein and gluten but amino acid release was a little less for the gluten. With sodium phytate, the release of peptides was quite similar for casein but was less for gluten. The release of amino acids was diminished in both cases. Thus, gluten was more resistant than casein to the action of pancreatic enzymes. Nevertheless, this was not necessarily observed when those enzymes were used for proteolysis at a high enzyme/substrate ratio or following a high peptic proteolysis. The differences between casein and gluten proteolyses have been discussed according to the specific action of the pancreatic enzymes. In conclusion, in comparing the proteolyses of various foods, it is important to use various enzyme/substrate ratios.
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PMID:[In vitro proteolysis of casein and gluten by pancreatic enzymes]. 681 34

Dielectric heating at frequencies of 42 and 2450 MHz was applied to whole soybeans of natural moisture content for varies exposure times. The minimum energy absorbed (MEA) was calculated from moisture-loss and temperature-elevation data. Biochemical analyses were performed to determine protein dispersibility index (PDI), nitrogen solubility index (NSI), and trypsin-inhibitor, urease, lipoxygenase, and peroxidase activities. Because the heating rates were different at the two frequencies for the power levels used, plots of the biochemical properties against temperature of exposure time showed an apparent frequency dependence. This dependence on frequency disappeared, however, when MEA was substituted as the independent variable. Chemical analyses revealed that dielectric heating of soybeans at natural moisture levels should be as effective as conventional steam toasting in reducing trypsin-inhibitor activity. PDI and NSI, but not urease, were suitable indicators of trypsin-inhibitor inactivation by dielectric heating. Lipoxygenase was completely inactivated by the dielectric-heating treatments that gave suitable trypsin-inhibitor inactivation, but peroxidase activity remained relatively high, offering possible advantages for bleaching and improved soy product color.
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PMID:Effects of 42- and 2450-MHz dielectric heating on nutrition-related properties of soybeans. 692 Apr 15

Some patients with cystic fibrosis (CF) have malabsorption of fat and protein in spite of large amounts of supplemental pancreatic enzymes. This is partly due to acid inactivation of exogenous pancreatic enzymes in the stomach. The effect of cimetidine on gastric function and exogenous pancreatic enzymes was assessed by a marker perfusion technique in 4 CF children in a double-blind controlled fashion. Gastric acid secretion was higher in CF patients than in controls (P less than 0.005) and was reduced significantly by oral cimetidine (P less than 0.02). Rapid inactivation of exogenous trypsin and lipase occurred when gastric pH fell to less than 4.5. There was no loss of enzyme activity during treatment with cimetidine when gastric pH remained above 5.5. Activity of lipase and trypsin in the jejunum improved in all subjects. Fat and nitrogen absorption assessed by a balance technique during the study period showed a small improvement in fat absorption while on cimetidine. We conclude that some CF patients have a high meal-stimulated gastric acid output which causes inactivation of trypsin and lipase. Cimetidine was effective in reducing acid secretion in such patients and led to small improvements in fat absorption.
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PMID:The effect of cimetidine on meal-stimulated gastric function and exogenous pancreatic enzymes in cystic fibrosis. 692 76

Pancreatic secretion in rats was assessed by measuring the amounts of p-aminobenzoic acid (PABH) excreted in urine after oral administration of Ac-L-Tyr-PAB, and by determination of enzyme activity in pancreas and faeces. 3 groups of 7 rats were kept on diets with casein as the main source of nitrogen without (control K0) or with two levels of trypsin inhibitor (K1 and K2). Two other groups were fed diets with 40 and 80% of casein substituted by raw soya bean protein and having trypsin inhibitor contents equivalent to those in diets K1 and K2. Urinary excretion of PABH ranged from 99 to 105% of intake and were not different between control and experimental rats. The weight of pancreas and pancreatic activities of trypsin and chymotrypsin in all experimental rats were higher than in controls. The activity of chymotrypsin in the faeces of rats of groups K1 and K2 was greater than in K0 while in groups S1 and S2 it was about five times that in groups K1 and K2. Generally, it was greater on diets with more trypsin inhibitor. The activity of trypsin in the faeces of rats K0, K1 and S1 was several times less than in K2 and S2. It has been concluded that measurement of trypsin and chymotrypsin in faeces allows to estimate differences in the secretion of pancreatic enzymes.
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PMID:Use of Ac-L-Tyr-PAB for estimating the activity of chymotrypsin in rats. 698 85


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