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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High concentrations of either trypsin or chymotrypsin caused nearly complete cleavage of capsid protein VP2 of hepatitis A virus but did not significantly reduce the infectivity, thermostability, or antigenicity of the virus. Chymotrypsin also had a lesser effect on VP1. These findings indicate the presence of a protease-accessible VP2 surface site which neither contributes significantly to the dominant antigenic site nor plays a role in the attachment of the virus to putative cell receptors.
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PMID:Protease digestion of hepatitis A virus: disparate effects on capsid proteins, antigenicity, and infectivity. 165 60

The inactivation of native glutamine synthetase (GS) from Bacillus subtilis by trypsin, chymotrypsin, or subtilisin followed pseudo-fast order kinetics. Trypsin cleaved the polypeptide chain of GS into two principal fragments, one of about 43,000 (Mr) and the other of smaller than 10,000. Chymotrypsin and subtilisin caused similar cleavage of GS. A large fragment (Mr 35,000) and one smaller than 10,000 were detected on SDS-PAGE. The nicked protein remained dodecameric, as observed on gel filtration, electrophoresis, and electron micrography. In the presence of glutamate, ATP, and Mn2+, the digestion of GS by each of the three proteases was retarded completely; however, the presence of one substrate, L-glutamate, ATP+Mn2+, or ATP+Mg2+ led to partial protection. The product, L-glutamine, did not retard but altered the susceptibility of the protease sensitive sites. Amino acid sequence analysis of the two smaller polypeptide fragments showed that the nicked region was around serine 375 and serine 311, respectively, and that both large fragments (43,000 and 35,000) were N-terminal polypeptides of GS. The serine 311 region was involved in the formation of the enzyme-substrate complex. Tyrosine 372 near serine 375 corresponded to tyrosine 397 which was adenylylated by adenyltransferase in Escherichia coli GS.
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PMID:Characterization of Bacillus subtilis glutamine synthetase by limited proteolysis. 168 34

Pancreatic enzyme secretion in rats has been shown to be stimulated differentially by the intestinal hormones secretin and cholecystokinin. Since it is unknown if activation of neural mechanisms have similar effects, it was the aim of the present study to examine in anesthetized rats the output of the pancreatic enzymes amylase, lipase, trypsin, and chymotrypsin before (15 min), during, and after (30 min each) vagal stimulation (5 ms, 10 V) with different frequencies (0.5, 5, 10, and 50 Hz). At 5 Hz, a maximal stimulation of all four enzymes was observed, with a peak towards the end of the vagal stimulation period. At 0.5 Hz, amylase, trypsin, and chymotrypsin were released not only in smaller quantities but also in a different time pattern (trypsin and chymotrypsin), with a maximum early during vagal stimulation. Lipase secretion remained unchanged at 0.5 Hz. At 10 Hz, the output of amylase, lipase, and trypsin was quantitatively less compared to 5 Hz. In contrast to stimulation at 0.5 and 5 Hz, the maximal enzyme output was reached after cessation of vagal stimulation (amylase and lipase). Chymotrypsin release did not change in response to vagal stimulation at 10 Hz. A frequency of 50 Hz had no influence on the secretion of any of the four enzymes determined. These data demonstrate that activation of the vagus nerves can lead to a differential release of pancreatic enzymes. The exact regulatory mechanisms of action are as yet unknown and remain to be determined.
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PMID:Frequency-dependent secretion of pancreatic amylase, lipase, trypsin, and chymotrypsin during vagal stimulation in rats. 170 Apr 13

We have examined in detail the kinetics of binding of the serpin alpha 2-antiplasmin to the serine proteases alpha-chymotrypsin and plasmin. These represent model systems for serpin binding. We find, in contrast to earlier published results with alpha 2-antiplasmin and plasmin, that binding is reversible, and slow binding kinetics can be observed, under appropriate conditions. Binding follows a two-step process with both enzymes, with the formation of an initial loose complex which then proceeds to a tightly bound complex. In the absence of lysine and analogues, equilibrium between alpha 2-antiplasmin and plasmin is achieved rapidly, with an overall inhibition constant (Ki') of 0.3 pM. In the presence of tranexamic acid or 6-aminohexanoic acid, lysine analogues that mimic the effects of fibrin, plasmin binding kinetics are changed such that equilibrium is reached slowly following a lag phase after mixing of enzyme and inhibitor. The Ki' is also affected, rising to 2 pM in the presence of 6-aminohexanoic acid concentrations above 15 mM. Thus extrapolation to the in vivo situation indicates that complex formation in the presence of fibrin will be delayed, allowing a burst of enzyme activity following plasmin generation, but a tight, pseudoirreversible complex will result eventually. Chymotrypsin is more weakly inhibited by alpha 2-antiplasmin, exhibiting an overall Ki' of 0.1 nM, after two-stage complex formation. The inhibition constant for the initial loose complex (Ki) is very similar for both enzymes. The difference in binding strength between the two enzymes is accounted for by the dissociation rate constant of the second step of complex formation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Serpin-serine protease binding kinetics: alpha 2-antiplasmin as a model inhibitor. 170 40

We have shown that depletion of monocytes from human peripheral blood mononuclear cells (PBMC) by L-phenylalanine methyl ester (PheOMe) enhanced lymphokine-activated killer cell (LAK) generation by recombinant interleukin-2 (rIL-2) at high cell density. In this study, we have investigated the mechanism of action of PheOMe on LAK activation by using trypsin, chymotrypsin, tosylphenylalaninechloromethanol (TPCK, a chymotrypsin inhibitor), tosyl-L-lysinechloromethane (TLCK, a trypsin inhibitor), phenylalaninol (PheOH), and benzamidine. PBMC were treated with 1-5 mM PheOMe for 40 min at room temperature in combination with the various agents, washed and assessed for their effects on natural killer (NK) activity against K562 cells and monocyte depletion. The treated cells were then cultured with or without rIL-2 for 3 days. LAK cytotoxicity was assayed against 51Cr-labeled K562 and Raji tumor target cells. TPCK at 10 micrograms/ml partially inhibited depletion of monocytes by PheOMe. TLCK did not prevent depletion of monocytes nor inhibition of NK activity induced by PheOMe. TPCK and TLCK inhibited NK activity by themselves. TPCK but not TLCK inhibited rIL-2 induction of LAK cells. On the other hand, PheOH and benzamidine (analogs of PheOMe) lacked any effect on monocyte depletion but abrogated the inhibitory effect of PheOMe on NK activity. They had no effect on rIL-2 activation of LAK activity enhanced by PheOMe. Trypsin potentiated the inhibitory effect of PheOMe on NK activity and monocyte depletion. Trypsin partially inhibited IL-2 activation of LAK activity enhanced by PheOMe. Chymotrypsin had little effect on NK activity but prevented the inhibitory effect of PheOMe on NK activity. It had little effect on monocyte depletion induced by PheOMe. PheOMe was hydrolysed by monocytes and chymotrypsin to Phe and methanol as determined by HPLC. TPCK inhibited hydrolysis of PheOMe by monocytes. Our data suggest that the effects of PheOMe on monocytes, NK cells and LAK activation involve protease activities of monocytes.
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PMID:Human lymphokine-activated killer (LAK) cells: III. Effect of L-phenylalanine methyl ester on LAK cell activation from human peripheral blood mononuclear cells: possible protease involvement of monocytes, natural killer cells and LAK cells. 176 Aug 8

Two carboxyacyl derivatives of cardiolipin, O-succinyl- and O-glutarylcardiolipin, were synthesized with the aim of using them as artificial membrane anchors for the immobilization of hydrophilic proteins to liposomes. Four adjacent fatty acid residues can be introduced into a protein with only one single amino group being blocked, by reacting the cardiolipin derivatives with the protein amino groups after carbodiimide activation. alpha-Chymotrypsin, used as a model protein, and modified with on average two molecules of O-succinylcardiolipin was incorporated into liposomes, which had been prepared by different methods, with very high yield. If incorporated in preformed liposomes, the carboxyacyl cardiolipin anchors were also efficient in binding proteins to liposomal surfaces. Up to 350 micrograms chymotrypsin/mumol lipid were coupled to small unilamellar vesicles, preserving reactivity of the enzyme towards specific macromolecular inhibitors. Human IgG could also be bound to anchor-containing liposomes with high protein to lipid coupling ratio as well as high coupling yield.
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PMID:Carboxyacyl derivatives of cardiolipin as four-tailed hydrophobic anchors for the covalent coupling of hydrophilic proteins to liposomes. 176 52

11 amino acid derivatives were tested as alpha-chymotrypsin substrates in the esterification reaction with methanol in organic media. The reactions were carried out in water-saturated ethyl acetate and in acetonitrile containing 4% water. alpha-Chymotrypsin adsorbed on Celite was used as a catalyst. From initial reaction rate measurements, the Michaelis-Menten parameters Vmax and KM were determined. All the amino acid derivatives tested were esterified, and the highest values of kcat/KM were obtained with the N-acylated aromatic amino acids. Correlations between Michaelis-Menten parameters and physical properties of the substrates such as molar refractivity (MR) and log P were deduced. The results show that the specificity of the alpha-chymotrypsin towards the side chain of the amino acids in organic media is the same as that in aqueous media. However, the specificity towards the N-protecting group is opposite to that in water, so the reaction medium affects the interaction of this part of the molecule with the enzyme to a large extent.
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PMID:Substrate specificity of alpha-chymotrypsin-catalyzed esterification in organic media. 176 79

The effects of bolus intravenous injections of various serine proteases (thrombin, trypsin, plasmin, neutrophil elastase and chymotrypsin) on arterial blood pressure were evaluated in anesthetized, normotensive rats. The activity to intravenous trypsin was also studied in anesthetized, normotensive dogs. In the rat, both thrombin (0.33-10 nmol/kg) and trypsin (4.2-420 nmol/kg) produced pronounced vasodepressor responses. The activity on blood pressure was observed immediately following injection of either protease, and both the magnitude and duration of the responses were dose dependent. Plasmin (37-350 nmol/kg) and neutrophil elastase (91-910 nmol/kg) also induced dose-dependent hypotension but at much higher dose levels. In addition, the magnitude of the blood pressure responses after plasmin and neutrophil elastase was less than those produced by thrombin and trypsin. Chymotrypsin, on the other hand, had a more diverse blood pressure profile. The protease induced a modest decrease in pressure at doses of 40 and 120 nmol/kg, a pressor response after 400 and 1,200 nmol/kg and at the highest dose tested (4,000 nmol/kg) profound hypotension. In the dog, trypsin produced a dose-dependent vasodepressor response similar to that observed in the rat. The doses of proteases producing alterations of blood pressure in the rat correlated inversely with the ability of rat serum or plasma to completely inhibit those proteases. The pharmacology of the trypsin or thrombin blood pressure response suggests the requirement of specific active enzymes to mediate the vasodepression induced by both proteases.
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PMID:Acute blood pressure effects of selected serine proteases in normotensive rats and dogs. 177 Nov 72

In 96 consecutive patients who underwent a 72-h faecal fat determination because of suspected nutrient malassimilation (maldigestion and/or malabsorption) faecal chymotrypsin (F-Chym) was estimated with a commercial photometric test (Monotest Chymotrypsin), comparing F-Chym concentrations in the first 24-h stool with the total 72-h F-Chym output. In the first 24-h faeces, the F-Chym concentration, calculated as a mean of three random samples, did not significantly differ from a single value obtained after homogenization. In known pancreatic disease, a F-Chym concentration less than 3.0 U/g wet faeces distinguished well between steatorrhoic patients (n = 12) and nonsteatorrhoic (n = 13) (positive predictive value (PV), 91%; negative PV, 86%) but was less suitable as a screening test for pancreatic steatorrhoea in the unselected patient group (positive PV, 61%; negative PV, 98%). Although the estimation of 72-h F-Chym output could differentiate between various subgroups of patients to a certain extent, the positive PV for discovery of pancreatic steatorrhoea in a single patient was low. Four patients had excessively high F-Chym output and increased bile acid excretion after ileal resection (n = 3) and radiation ileitis (n = 1), respectively, possibly indicating the removal of an inhibitory mechanism of pancreatic and biliary secretion in these conditions.
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PMID:Determination of faecal chymotrypsin concentration and 72-hour faecal chymotrypsin output in the detection of pancreatic steatorrhoea. 177 36

alpha-Chymotrypsin was deposited on Celite and the resulting immobilized preparations were used to carry out peptide synthesis reactions in organic media with only small amounts of water present. The influence of different parts of the donor ester and acceptor nucleophile substrate molecules on the kinetics of the enzymatic reactions was studied. The specificity of alpha-chymotrypsin in organic media was a combination of its substrate specificity in aqueous media and solvent effects. The kinetics of peptide synthesis can thus be modulated by using suitable solvents and protecting groups.
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PMID:Catalytic properties of alpha-chymotrypsin in organic media. 182 61


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