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)

Ciliary neurotrophic factor (CNTF) is a protein supporting the in vitro survival of a characteristic spectrum of embryonic chicken and rat peripheral neurons. High-speed supernatants of extracts from two neuroblastoma (NB) cell lines--the mouse C 1300 N2a and the human IMR 32--mimic the effects of CNTF on identical target neurons. Promotion of survival is dose-dependent with an ED50 of 80 micrograms (IMR 32) and 140 micrograms (C 1300 N2a) of protein per ml and saturable at plateau values for surviving neurons identical to those achieved with purified CNTF. Small amounts of a CNTF-like material are also detectable in medium conditioned by NB cells. The activity is destroyed by heat and trypsin and not blocked by antibodies to (mouse) nerve growth factor. Unlike the neurite-promoting and neuronal-survival modulating agent laminin, it cannot be depleted on poly(L-alpha-ornithine)-coated plastic surfaces. NB IMR 32 cell extracts were electrophoresed using NaDodSO4/PAGE and transferred to nitrocellulose. Ciliary ganglion neurons seeded on the blotting paper in culture medium lacking CNTF ("cell blot") exclusively survive on two distinct bands with apparent molecular masses of 24 and 48 kDa. Twenty-four kilodaltons is the molecular mass of a CNTF purified from rat sciatic nerve. These results suggest that NB cells may contain a CNTF-like protein and provide further evidence that neurons may store neurotrophic factors. Purified (chicken) CNTF failed to affect proliferation and neurite growth of NB cells. The biological relevance of CNTF for NB cells, therefore, remains to be elucidated.
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PMID:Neuroblastoma cells contain a trophic factor sharing biological and molecular properties with ciliary neurotrophic factor. 347 25

We have purified from beef liver an enzyme which decarbamoylates carbamoyl-hemoglobin and to a much lesser extent carbamoyl histones. Carbamoyl casein was a poor substrate while carbamoyl trypsin, fibrinogen and ovoalbumin were not affected. The optimal pH is 7.4. Addition of Mg++, Mn++ or Ca++ was without effect. On testing citrulline as a substrate we found high activity leading us to suspect that the activity of the decarbamoylase preparation was due to contaminating ornithine transcarbamoylase activity. Evidence for this is the similar ratio of transcarbamoylase to decarbamoylase activities of both ornithine transcarbamoylase and of the purified preparation of decarbamoylase from beef liver. Also, delta-PALO, the specific inhibitor of ornithine transcarbamoylase inhibited both preparations to the same extent. Interestingly, ornithine transcarbamoylase from bacteria also has decarbamoylase activity while aspartic transcarbamoylase does not.
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PMID:Decarbamoylating activity of ornithine transcarbamoylase. 398 80

Walls of the pigmented strain of Micrococcus radiodurans showed several layers in the electron microscope. These layers include an outermost network structure removed by trypsin, a fragile soft layer containing hexagonally packed subunits, and a rigid layer penetrated by numerous holes. The two inner layers were separated by a process of autolysis, trypsin treatment, and gradient centrifugation. The hexagonally packed layer was less dense, pink in color, and it contained carotenoids, lipid, protein, and polysaccharide. The lipid consisted of odd-numbered as well as even-numbered fatty acids, and the polysaccharide contained rhamnose and mannose, but it did not contain heptose. The "holey" layer was white and was composed of a mucopeptide containing glucosamine, muramic acid, and four main amino acids (glutamic acid, alanine, glycine, and l-ornithine, in the ratios of 1:1.7:1.8:1.2, respectively). This layer also contained phosphorus, glucose, and a trace of meso- and ll-diaminopimelic acid. A white mutant, W(1), of M. radiodurans had no pigment or lipid in its walls, but it contained small amounts of the "hexagonal" layer. The holey layer, constituting the bulk of the wall, was similar in morphology and composition to that layer in the pigmented strain. Lysozyme did not remove the lipoprotein-polysaccharide component from the walls of the pigmented strains, and the hexagonally packed structure was not visibly affected, except for change in a minor structure. Most of the mucopeptide layer was solubilized by lysozyme, but a structureless bag-shaped residue was left. This residue contained phosphorus, carbohydrate, and limited amino acids, but it did not contain muramic acid, glucosamine, or ornithine. Aqueous phenol removed a lipoprotein component from strain R(1), which contained limited fatty acids. It also removed meso- and ll-diaminopimelic acid.
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PMID:Morphology and chemistry of cell walls of Micrococcus radiodurans. 564 Mar 86

1. Esters of gamma-guanidino-l-alpha-toluene-p-sulphonamidobutyric acid (alpha-N-toluene-p-sulphonyl-l-norarginine) have been synthesized and shown to be hydrolysed by bovine trypsin and thrombin. As substrates for these enzymes, they were better than esters of alpha-N-toluene-p-sulphonyl-l-homoarginine or of alpha-N-toluene-p-sulphonyl-l-ornithine but not as good as esters of alpha-N-toluene-p-sulphonyl-l-arginine. 2. With trypsin as catalyst, the methyl and propyl esters are hydrolysed at the same rate at high substrate concentrations and hence deacylation of the acyl-enzyme appears to be rate-determining. In the presence of thrombin, however, the methyl ester is hydrolysed much faster than the n-propyl ester. 3. The variation of k(0) with pH indicates that groups with pK((app.)) values of 7.05+/-0.02 and 6.53+/-0.02 must be dissociated in trypsin and thrombin respectively for hydrolysis to proceed. 4. Activation constants have been determined for the trypsin-catalysed hydrolysis of methyl gamma-guanidino-l-alpha-toluene-p-sulphonamidobutyrate and have been compared with the corresponding constants for the hydrolysis of homologous substrates. 5. Cholate increases k(0) and decreases K(m); the effects are more pronounced with thrombin than with trypsin.
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PMID:Kinetics and mechanism of catalysis by proteolytic enzymes. The kinetics of hydrolysis of esters of gamma-guanidino-L-alpha-toluene-p-sulphonamidobutyric acid by bovine trypsin and thrombin. 586 13

The production of urea and ornithine is increased greatly in spleen cell cultures of an allograft recipient in the presence of donor cells (secondary MLC) in comparison to that of primary MLC (without previous allograft). This phenomenon appears after 24 hr of culture and reaches its maximum at 48 hr. The greatest increase in urea production is observed when the recipient spleen cells are collected at the time of allograft rejection. To obtain this extra production of urea, the stimulating cells in MLC should specifically be of the donor type or at least bear one homology with donor cells at the K or D locus. The increased production of urea and ornithine during MLC results from the action of a lymphokine released by recipient cells in the presence of donor cells. This factor acts upon cells present in bone marrow, spleen, and elicited peritoneal cells but is absent or is present in smaller quantities in thymus and lymph node cells. Target cells of this factor possess numerous macrophage features and could be immature cells of the macrophage line. The lymphokine responsible for this phenomenon is heat-stable, destroyed by trypsin, chymotrypsin, and neuraminidase, and has a m.w. around 32,000. It acts upon its target cells by increasing arginase activity, which results in the production of a large amount of ornithine, an important precursor of polyamine biosynthesis.
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PMID:Evidence for a lymphokine enhancing arginase activity during allograft rejection. 618 26

The influence of a raw green gram (RGG) diet, an autoclaved green gram (AGG) diet and green gram trypsin inhibitors (GGTI) incorporated in AGG diet on urinary and blood urea and creatinine levels in rats was studied. The activities of certain liver enzymes of pathways associated with protein or amino acid metabolism were also studied. The levels of urea and creatinine in urine and blood were found to be significantly increased in rats fed the RGG and GGTI-incorporated AGG diets when compared to the animals fed with the AGG diet. The levels of enzyme activities of arginase, ornithine transcarbamoylase, aspartate aminotransferase and alanine aminotransferase were also found to be significantly increased along with that of urea and creatinine, The possible role of GGTI on the altered levels of the above-mentioned parameters is discussed.
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PMID:Influence of dietary raw green gram (Phaseolus aureus Roxb) and green gram trypsin inhibitors on the activity of certain protein metabolism enzymes in rats. 733 25

Kinetics of the bovine beta-trypsin (trypsin) reaction with the active site titrant N alpha-(N,N-dimethylcarbamoyl)- alpha-aza-ornithine p-nitrophenyl ester (Dmc-azaOrn-ONp) was obtained at pH 6.2 and 21.0 degrees C. The results are consistent with the minimum three-step catalytic mechanism of serine proteinases involving a stable acyl.enzyme adduct. Dmc-azaOrn-ONp binds stoichiometrically to trypsin and allows the reliable determination of the active enzyme concentration between 1.0 x 10(-6) M and 3.0 x 10(-4) M. The three-dimensional structure of the trypsin.Dmc-azaOrn acyl.enzyme adduct has been solved by X-ray crystallography at 1.8 A resolution (R = 0.153). The Dmc-azaOrn moiety of the active site titrant is accommodated in the serine proteinase active center, occupying the S1 specificity subsite, and is covalently linked to the OG atom of the Ser195 catalytic residue.
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PMID:Inhibition of bovine beta-trypsin by the active site titrant N alpha-(N,N-dimethylcarbamoyl)-alpha-azaornithine p-nitrophenyl ester: a kinetic and X-ray crystallographic study. 750 19

The effect of repeated oral administration of prostaglandin analogue (dmPGE2) on intestinal macromolecular transport and digestive enzymes development were investigated in the suckling rats. By the administration of dmPGE2 for 7 days, precocious induction of maltase activity, depression of amylase activity and enhancement of trypsin activity in the pancreas occurred. Absorption of bovine IgG was dose dependently depressed by dmPGE2 treatments. The intestinal cessation was also observed in the adrenalectomized pups, but was not influenced by difluoromethyl ornithine administration. These results suggest that oral administration of PGE2 induces precocious maturation of the small intestine and exocrine pancreas and that the intestinal cessation is not directly related to ornithine decarboxylase activity in the suckling rats.
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PMID:Precocious cessation of intestinal macromolecular transport and digestive enzymes development by prostaglandin E2 in suckling rats. 752 52

A peptide mixture containing 21 peptide sequences has been constructed to test the Bowman-Birk inhibitor reactive-site loop motif as the basis of inhibition for a range of serine proteases. The 21 peptides are all based on an 11 amino acid sequence designed from a Bowman-Birk like inhibitor reactive-site loop. Variation has been introduced at the P1 site of the loop, which has been randomised to include all the natural L-amino acids (except for cysteine), plus the non-natural L-amino acids ornithine and norleucine, The mixture of peptides was screened for specific binding to immobilised porcine pancreatic elastase, subtilisin BPN', alpha-chymotrypsin, trypsin, anhydro-alpha-chymotrypsin and anhydrotrypsin. Five peptides from the mixture bind to alpha-chymotrypsin, two of which also bind to anhydro-alpha-chymotrypsin, and two peptides bind trypsin, neither of which binds to anhydro-trypsin. The competitive inhibition constants (K(i)) and the rates of proteolytic hydrolysis of the individual peptides with their respective enzymes were determined. The rates of hydrolysis were found to vary widely and show little correlation with the K(i) values. In the case of the alpha-chymotrypsin inhibitors, the peptides with the lowest K(i) (0.1-0.05 mM) were the only peptides that bound to anhydro-alpha-chymotrypsin. However, no peptides bound to anhydrotrypsin, suggesting a fundamental difference in the way that alpha-chymotrypsin and trypsin are inhibited by these cyclic peptides.
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PMID:Synthesis of a mixture of cyclic peptides based on the Bowman-Birk reactive site loop to screen for serine protease inhibitors. 755 1

Trypanosoma brucei ornithine decarboxylase was reconstituted by coexpression of two polypeptides corresponding to residues 1-305 and residues 306-425 in Escherichia coli. The two peptides were coexpressed, at wild-type levels, from a single transcriptional unit that was separated by a 15-nucleotide untranslated region containing a ribosome binding site. The fragmented enzyme was purified and analyzed. The N- and C-terminal peptides are tightly associated into a fully active tetramer which has the same molecular weight as the native dimer. The kinetic constants (Km and kcat) measured for the decarboxylation of ornithine are identical to those obtained for the wild-type enzyme. These results suggest that the enzyme is organized into two structural domains, with a domain boundary in the region of amino acid 305. In contrast, the individual N- and C-terminal peptides are expressed primarily as inclusion bodies. Small quantities of soluble N-terminal peptide could be purified. This truncated protein is capable of inhibiting the wild-type enzyme, suggesting that it is folded into a native-like structure. Limited proteolysis with trypsin or chymotrypsin identifies a likely surface loop at amino acids 160-170, present in both the mouse and T. brucei enzyme, which positions one or more functionally important active site residues (e.g., Lys169). Kinetic analysis of a chimeric enzyme composed of T. brucei and mouse ornithine decarboxylase suggests that the substrate carboxylate binding determinant is located between residues 1 and 170.
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PMID:Domain organization and a protease-sensitive loop in eukaryotic ornithine decarboxylase. 757 30


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