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 compartmentation of fast-transported proteins that possess sulfated tyrosine residues--sulfoproteins--has been examined for further resolution of the possible significance of sulfated tyrosine in routing and delivery of fast-transported proteins. In vitro fast axonal transport of [35S]methionine- or 35SO4-labeled proteins was measured in dorsal root ganglion neurons for analysis of protein compartmentation en route and in synaptic regions. When membrane fractions were exposed to Na2CO3 for separation of "lumenal" and peripheral membrane proteins from integral components of the membrane, approximately 20% of the [35S]methionine incorporated into fast-transported proteins was present in a carbonate-releasable form in the axon, whereas 53% of the incorporated 35SO4 was released by carbonate. Eighty percent of the 35SO4 in this releasable fraction was acid labile, typical of sulfate ester-linked to tyrosine. Sulfoproteins were also detected in synaptosomes and were released into the extracellular medium in a calcium-dependent fashion, an observation suggesting that fast-transported sulfoproteins are secreted. Of the remaining 47% of the fast-transported 35SO4-labeled proteins resistant to carbonate treatment (the integral membrane protein fraction), nearly 60% of the 35SO4 was acid labile. Other membrane stripping agents, such as 0.1 M NaOH, 0.5 M NaCl, or mild trypsin treatment, failed to remove acid-labile 35SO4-labeled species from carbonate-treated membrane. Quantitative comparisons of several of the most abundant sulfoproteins resolved via two-dimensional gel electrophoresis confirmed that approximately 7% of each of the species remained associated with carbonate-treated membranes, presumably as integral membrane components.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Complex compartmentation of tyrosine sulfate-containing proteins undergoing fast axonal transport. 243 47

A multi-channel small diameter tube was used to study the secretion of bicarbonate by 3 cm long segments of the proximal duodenum isolated between balloons. The tube had an outer diameter of 5.3 mm and two central and four smaller, peripheral channels. Measurements of infused phenol red, 14C-PEG and vitamin B12 and of trypsin activity were performed to rule out contamination of the perfusate by gastric and pancreatic secretions. Basal secretion of bicarbonate by the duodenal mucosa in healthy subjects varied between 135 and 220 mumol/cm of intestine per hour. Perfusion of the lumen with acid (100 mM HCl for five minutes) increased the secretion to greater than 400 mumol/cm/h and the alpha 2-adrenoreceptor agonist clonidine (150 micrograms iv) decreased the HCO3- secretion by 70 mumol/cm/h. Clonidine simultaneously reduced the mean arterial blood pressure and plasma noradrenaline concentration, but did not affect the plasma glucose or adrenaline concentration. Duodenal bicarbonate secretion is important in the protection of this mucosa against acid discharged from the stomach. Increased sympathetic activity may, by inhibiting the bicarbonate secretion, decrease the protection in proximal duodenum in man and facilitate ulceration.
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PMID:Duodenal mucosal bicarbonate secretion in man. Stimulation by acid and inhibition by the alpha 2-adrenoceptor agonist clonidine. 255 85

The molecular properties of the neuron-specific, synaptic-enriched glycoprotein GP50 have been investigated with the aid of the monoclonal antibody MabSM-GP50. GP50 immunoreactivity was detected in the brains of the frog, trout, pigeon, snake, rabbit, mouse, cow, and human, although variation in quantity and electrophoretic mobility of the immunoreactive protein between species was apparent. Deglycosylation of synaptic membranes (SMs) with endoglycosidase H, peptide:N-glycosidase F, trifluoromethane-sulfonic acid, and alkaline sodium borohydride indicated that GP50 is associated primarily, if not exclusively, with high-mannose and/or hybrid-type oligosaccharides and lacks complex N-linked and O-linked sugar chains. GP50 remained associated with the membrane fraction following extraction of SMs with alkaline sodium carbonate, was partially (55%) present in the detergent phase following the phase partitioning of SMs in the presence of Triton X-114, and was resistant to proteolytic digestion with trypsin when present as a component of intact membranes. Taken together, these results indicate that GP50 is an integral component of the SM. Sucrose gradient centrifugation of Triton X-100 extracts of SMs or of forebrain and cerebellar homogenates resolved GP50 into two fractions with sedimentation coefficients of 3.6S and 7.3S, which accounted for 45 and 55% of the total, respectively. The 7.3S form occurred exclusively in the aqueous phase following partitioning with Triton X-114, whereas the 3.6S species was found in both the aqueous and detergent phases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular characterization of GP50: a neuron-specific, synaptic-enriched glycoprotein. 280 1

Silicas of different particle and pore sizes were derivatized with three different silanes. The functionalized silica contained either epoxide, methacrylate or amino groups. These groups were further modified to yield primary hydroxyl functions. Activation of the resultant primary hydroxyl groups for the purpose of chemically coupling proteins was studied with a variety of reagents and optimized for p-nitro-phenyl chloroformate. The effect of pH on the efficiency of coupling proteins (BSA and trypsin) to p-nitrophenyl carbonate-silica was studied in detail. Slightly acidic conditions (pH 6) gave the highest yields. In a dynamic recycling process, bovine pancreatic trypsin inhibitor was immobilized to activated primary hydroxyl-silica packed into a stainless-steel column. The high-performance affinity chromatography purification of trypsin on this column is demonstrated.
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PMID:Coupling of ligands to primary hydroxyl-containing silica for high-performance affinity chromatography. Optimization of conditions. 282 Oct 35

Cytochrome c1 is an amphiphilic protein which binds to the mitochondrial inner membrane, presumably through a hydrophobic region near the carboxyl (C)-terminus. In the preceding study (Hase, T., et al. (1987) J. Biochem. 102, 401-410), two cytochrome c1 mutations were constructed: delta 1 and delta 2 cytochromes c1, in which the C-terminal segments of 17 and 71 residues were replaced by foreign sequences of 20 and 15 residues, respectively. delta 2 cytochrome c1 had lost the putative membrane anchor. The two cytochrome c1 mutants were localized in mitochondria, but succinate-cytochrome c1 reductase activity was detected only in the mitochondria containing delta 1 cytochrome c1. The membrane association of the two mutant molecules as well as that of authentic cytochrome c1 was investigated. These three molecules were firmly attached to mitochondrial membranes and not solubilized on either sonication or sodium carbonate (pH 11) treatment. However, when the membranes were solubilized with Triton X-100, both the delta 1 and authentic cytochromes c1 were extracted from the membranes more easily than delta 2 cytochrome c1. By fractionating cholate extracts of mitochondrial membranes with ammonium sulfate, delta 1 cytochrome c1 was cofractionated with the enzymatic activity of complex III, but delta 2 cytochrome c1 was clearly separated from the complex III fraction. Trypsin treatment of mitochondria and mitoplasts showed that delta 2 cytochrome c1 was exposed to the intermembrane space, with such a topology that its trypsin susceptibility became much higher than that of the authentic molecule.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A carboxyl-terminal hydrophobic region of yeast cytochrome c1 is necessary for functional assembly into complex III of the respiratory chain. 282 89

Monoclonal antibodies were prepared against pancreatic stone protein, a protein which inhibits calcium carbonate precipitation. Two monoclonal antibodies designated D4 and 2E7 were characterized. Immunoadsorbant columns, obtained by linkage of these monoclonal antibodies to Affigel 10, have been used to isolate immunoreactive forms of pancreatic stone protein from nonactivated human pancreatic juice. These monoclonal antibodies permitted us to test the possible immunological relationship between pancreatic stone protein and human trypsin 1. No immunological similarity was found, in agreement with our previous results, and it was established that pancreatic stone protein is a novel protein and not a degradation product of human trypsin(ogen) 1.
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PMID:Monoclonal antibodies to pancreatic stone protein. Radioimmunoassay and immunological comparison with trypsin 1. 309 88

Pancreatic fluid and electrolyte secretion was assessed in 56 patients with cystic fibrosis (CF) and 56 non-CF control subjects undergoing pancreatic function testing while stimulated with cholecystokinin and secretin. Both CF patients and control subjects exhibited a wide range of pancreatic function. Fluid and trypsin outputs were positively correlated in both groups. Fluid output in CF subjects was significantly lower, however, than that of control subjects at any given level of trypsin output. Sodium, bicarbonate, and chloride secretions were all significantly decreased in CF subjects. Bicarbonate and chloride were important determinants of fluid secretion, but at any given bicarbonate or chloride output CF subjects secreted significantly less fluid than control subjects. When bicarbonate and chloride were analyzed as simultaneous predictor variables, adjusted fluid secretion was not significantly different in CF and control subjects. Diminished fluid secretion in CF subjects is therefore caused by impaired chloride, as well as bicarbonate, secretion.
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PMID:Impaired chloride secretion, as well as bicarbonate secretion, underlies the fluid secretory defect in the cystic fibrosis pancreas. 339 65

Cultures of human vascular endothelial cells were used to study the phenomenon of density-dependent inhibition of cell growth. Endothelial cells were disrupted by nitrogen cavitation, and a plasma membrane-enriched fraction was prepared by differential centrifugation followed in some cases by sucrose density gradient fractionation. Membrane suspension was added to low-density early-passage endothelial cultures grown in microwells. Hemocytometer cell counts and 6 hr 3H-thymidine pulses were performed in triplicate wells at varying intervals. Plasma membranes suppressed cell proliferation in a reversible, dose-dependent fashion. Increasing the ambient concentration of endothelial cell growth factor did not alter the inhibitory effect. The antiproliferative effect was sensitive to heat and trypsin and to incubation with 0.1 M sodium carbonate, pH 11.5. Membrane vesicles selectively derived from the apical cell surface also suppressed proliferation. This phenomenon showed at least some specificity for cell type and species in both human and bovine models. Therefore, cell-cell contact is capable of regulating endothelial cell proliferation in vitro despite the presence of available growth surfaces and of optimally supportive culture medium.
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PMID:Specific inhibition of endothelial cell proliferation by isolated endothelial plasma membranes. 373 92

In order to improve the taste, flavor and nutritional quality of chickpea (Cicer arietinum), various processing conditions were studied. The decorticated samples were processed under various conditions, either by presoaking or non-soaking in water or sodium carbonate solution. The proteins were also isolated from water or carbonate-presoaked chickpea and subjected to various processing. Carbonate-presoaked samples gave slightly lower protein and ash values. No major changes in other constituents were observed. Subjective analysis of the intensity of characteristic chickpea flavor in processed samples was carried out, indicating some improvement in the carbonate-presoaked samples. Carbonate-treated samples exhibited a lighter color. The carbonate presoaking procedure had no adverse effect on the availability of lysine and nitrogen solubility index (NSI), as compared to the water-presoaking procedure. The time required to inactivate trypsin inhibitors in carbonate-presoaked chickpea at boiling temperature, was half that required in the case of water-presoaked ones. Under the conditions used in treating chickpea with sodium carbonate, no beneficial effect was observed in reducing the tannin content. No significant differences were observed in net protein ratio (NPR) among the various processed chickpea samples, even though in some cases isolated protein gave significantly lower NPR values. Digestibility values were higher for isolated protein than for whole chickpea samples.
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PMID:Studies on the development of infant foods from plant protein sources. Part II. Effect of processing conditions on the chemical and nutritive properties of chickpea (Cicer arietinum). 384 55

A cell surface preparation from confluent endothelial cells can inhibit DNA synthesis of actively growing endothelial cells. The decrease in the rate of [3H]thymidine incorporation is concentration dependent and levels off at 47% of the control. The preparation has no affect on the growth of vascular smooth muscle cells. A similar preparation from smooth muscle cells does not show inhibitory activity with either endothelial or smooth muscle cells. The inhibition of growth can also be demonstrated by a decrease in thymidine index and growth rate. The inhibition is transient and after 48 h, the growth rate is similar to that of the control. In a wound edge assay, both migration and proliferation are inhibited. The inhibitory activity is partially labile to trypsin and abolished by pepsin, heating at 100 degrees C, or reduction. Cell surface iodination and analysis of the proteins removed by urea treatment by SDS polyacrylamide gel electrophoresis show at least 11 bands with apparent molecular weights from 250,000 to 18,000. These radiolabeled proteins, as well as the active component of the cell surface preparation, are sedimentable at 100,000 g for 1 h. They are both solubilized in 30 mM octyl glucoside but not by treatment with 0.1 M sodium carbonate, pH 11.5. These results suggest that the activity is due to a cell-surface membrane fraction and may provide a basis for studying the mechanism of density-dependent inhibition of growth in a normal cell of defined origin.
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PMID:The role of membrane-membrane interactions in the regulation of endothelial cell growth. 399 78


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