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)

Purified vaccina virus haemagglutinin (VHA) was found to be sensitive to trypsin both with regard to haemagglutinating capacity and antigenic property. Phospholipase C and lipase had no effect on the haemagglutination (HA). Both the HA and the antigenic property thus depend on the integrity of the protein part. The loss of HA after treatment with trypsin may be due to breakdown of an essential protein or to secondary rearrangement of the whole structure, including the lipid part. Cells infected with an HA negative mutant of vaccinia virus also lacked the antigenic part of VHA. The sedimentation constant of VHA from HeLa cells was about 50.
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PMID:The vaccinia virus haemagglutinin: enzyme sensitivity and some physiocochemical properties. 6 Aug 73

Highly purified vesicular stomatitis virus (VSV) was obtained from VSV-infected SV40-transformed hamster cell lines. Immunization with this virus protected hamsters against challenge with SV40-transformed cells (TSV5-cl2). This protection was obtained regardless of the source of the SV40-transformed cells (e.g. cat, rat, hamster) used to produce VSV, and was therefore associated with the SV40 tumor-specific transplantation antigen (SV40-TSTA). Furthermore, when grown on spontaneously transformed cell lines or on cells transformed by a different oncogenic DNA virus, such as polyoma virus, the VSV failed to protect against the SV40-induced tumor. It was concluded that the SV40-TSTA activity of purified VSV is due to the incorporation of SV40-TSTA within the viral envelope. When VSV was treated with proteolytic enzymes (bromelain, trypsin) no loss of TSTA-induced tumor rejection was observed, although VSV had lost its ability to induce virus-neutralizing antibody. This clearly demonstrates that the TSTA activity is not related to the viral spikes. Phospholipase C suppressed the TSTA activity but neutralizing activity was still detectable in the anti-VSV sera. The results presented here demonstrate that the protection afforded by VSV is highly specific. It is particularly interesting that SV40-TSTA activity may be conveyed by the lipid core of the viral envelope.
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PMID:SV40 tumor rejection induced by vesicular stomatitis virus bearing SV40 tumor-specific transplantation antigen (SV40-TSTA). I. Specificity of immunoprotection and effect of enzyme treatment on TSTA activity. 7 Dec 74

1. To elucidate the role of macrophages in fibrosis the effect of the SiO2-liberated macrophage factor was assessed on protein synthesis in granulation-tissue slices. SiO2 could be replaced by chrysotile asbestos. The active factor is found in the 45/55% sucrose interface of macrophage homogenate. 2. There is no evidence of the involvement of collagenase. 3. The SiO2 effect is not influenced by the addition of yeast RNA to the incubation medium. 4. At a small concentration of polyvinylpyridine-N-oxide (PVNO) protein synthesis in the granulation tissue slices is stimulated, but at higher concentrations PVNO prevented the liberation of the fibrogenic factor from macrophages by SiO2. 5. Phospholipase C and trypsin inhibited the effect of SiO2, which was partially abolished also by heating, and by repeated freezing and thawing. 6. The macrophage RNAse, its inhibitors and fibroblast mRNA are suggested as key factors in the development of fibrosis.
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PMID:Effect of SiO2-liberated macrophage factor on protein synthesis in connective tissue in vitro. 23 May 68

The effect of phospholipid depletion by phospholipases on the properties and formation of monoamine oxidase A and B been investigated. The enzyme was solubilized, partially purified, treated with phospholipases and subjected to get filtration to reduce the amount of enzyme-associated phospholipids. Phospholipase A treatment of the purified monoamine oxidase fraction had no effect on the deprenil inhibition pattern or the observed transition temperatures in the Arrhenius plots. However, the rate of enzyme inactivation by heat and trypsin were greatly increased but differences in rates of inactivation of monoamine oxidase A and B were still observed. Phospholipase C treatment of the enzyme fraction had no effect on the deprenil inhibition pattern, Arrhenius plots, heat stability or trypsin digestibility. The inhibition pattern of membrane-bound monoamine oxidase and the phospholipase-treated fractions by propargylamine showed a reduced substrate specificity compared to deprenil suggesting a hydrophobic region in the enzyme is a factor involved in the structural differences of monoamine oxidase A and B.
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PMID:Effect of phospholipid depletion by phospholipases on the properties and formation of the multiple monoamine oxidase forms in the rat liver. 72 88

Nerve growth factor (NGF) receptor binding in membrane fractions of rabbit superior cervical ganglia has been measured after treatment with a variety of enzymes, protein-modifying reagents, and ions. Receptor binding is degraded by low concentrations of trypsin but is much less sensitive to alpha-chymotrypsin. Low concentrations of phospholipase A from Vipera russelli decrease NGF receptor binding by lowering the number of binding sites, while phospholipase A preparations from Crotalus terrificus terrificus and bee venom do not affect binding. Phospholipase C and D, neuraminidase, DNase, and RNase have minimal effects on receptor binding. NGF receptor binding appears to be absolutely dependent upon calcium ion. Removal of calcium from the incubation medium greatly reduces binding as does treatment with EDTA. Maximal receptor binding occurs at 5 mM calcium. Magnesium and sodium are unable to substitute for calcium. Receptor binding is greatly reduced by treating membranes with 2-hydroxy-5-nitrobenzyl bromide, 2-methoxy-5-nitrobenzyl bromide, diazonium tetrazole, and tetranitromethane. NGF receptor sites can be protected from 2-hydroxy-5-nitrobenzyl bromide by incubation with NGF.
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PMID:Nerve growth factor receptor binding. Influence of enzymes, ions, and protein reagents. 80 4

Alpha-1 adrenergic agonists increase cardiac Purkinje fiber automaticity and elevate D-myo-inositol-trisphosphate (IP3) levels. To learn about the relationship between phosphoinositide metabolism and the modulation of cardiac rhythm, we used phospholipase C to activate phosphoinositide hydrolysis in an alpha-1 receptor-independent fashion and determined whether this intervention modulated automaticity. We used standard microelectrode techniques to study automaticity in adult Purkinje fiber bundles, fluorescence microscopy to study fura-2 fluorescence in isolated Purkinje and ventricular myocytes and standard biochemical techniques to measure inositol phosphate production in ventricular myocytes. Phospholipase C increased Purkinje fiber automaticity, a process that was enhanced by 10 mM lithium (which had no effect alone) and suppressed by verapamil or ryanodine (both 10 microM). Superfusion with 12-O-tetradecanoyl-phorbol-13-acetate phorbol ester, phospholipase D and A2, as well as L-alpha-phosphatidic acid, trypsin and D-myo-inositol-1-phosphate, D-myo-inositol-1,4-bisphosphate, IP3 and D-myo-inositol-1,4,5,6-tetrakisphosphate did not affect automatic rate or transmembrane potentials. Biochemical studies of ventricular myocytes demonstrated a phospholipase C-induced increase in intracellular and extracellular IP3, D-myo-inositol-1,4-bisphosphate and D-myo-inositol-1-phosphate at 3 min, with the extracellular increase persisting thereafter. Fluorescence microscopy with fura-2 revealed that phospholipase C increased systolic-free calcium.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Phospholipase C modulates automaticity of canine cardiac Purkinje fibers. 215 67

Trypsin and alpha-chymotrypsin effects on masked insulin receptors were studied. Phospholipase C treatment, incubation in a high ionic strength buffer or solubilization were used as alternative procedures for the unmasking of insulin receptors. These three methods expose receptor structures which are inaccessible to insulin in the current experimental conditions of binding assays without any significant change in binding affinity. Both exposed and masked receptors proved to be equally sensitive to trypsin and alpha-chymotrypsin degradation. At 25 degrees C, about 5 micrograms trypsin/ml for 50 min or 80 micrograms alpha-chymotrypsin/ml for 200 min were necessary in each case to cause a 50% inhibition of the binding of 125I-iodo insulin to microsomes. The results suggest that masked receptors are only nonfunctional to bind insulin but they are not located in compartments inaccessible to molecules present in the medium.
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PMID:Effect of proteolytic enzymes on masked insulin receptors in rat submaxillary gland microsomes. 337 53

Treatment with phospholipase C strongly protected monkey kidney (Vero) cells against diphtheria toxin and reduced the ability of the cells to bind 125I-labelled toxin. Treatment with phospholipase D and with trypsin also protected the cells, although to a lesser extent. Phospholipase A2 had no protective effect. Phospholipase C also protected fetal hamster kidney cells against the toxin. After removal of the enzymes, as well as after treatment of the cells with 4-acetamide 4'-isothiocyanostilbene 2,2'-disulfonic acid, diphtheria toxin binding capability was restored slowly, apparently by a process requiring protein synthesis, since cycloheximide blocked the restoration. The data indicate that both phospholipids and protein are involved in the binding sites for diphtheria toxin.
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PMID:Evidence that membrane phospholipids and protein are required for binding of diphtheria toxin in Vero cells. 404 83

The methylation of phospholipids by S-adenosyl-L-methionine was characterized in microsomes prepared from strips of rat aorta. In the presence of 0.5 microM S-adenosyl-L-methionine, endogenous phosphatidylethanolamine was methylated to form three products: phosphatidyl-N-monomethylethanolamine, phosphatidyl-N,N-dimethylethanolamine and phosphatidylcholine. In the presence of 150 microM S-adenosyl-L-methionine the methylation activity increased more than 50-fold and the principal radioactive product was phosphatidylcholine. Optimal activity was at pH 9 and no magnesium requirement was detected. Exogenous phosphatidylethanolamine, phosphatidyl-N-monomethylethanolamine and phosphatidyl-N,N-dimethylethanolamine served as substrates for the enzyme. The methylation of exogenous phosphatidyl-N,N-dimethylethanolamine proceeded at a slower rate. Incubation of trypsin with the aorta microsomes reduced the enzymatic activity and reduced the relative yield of phosphatidyl-N-monomethylethanolamine. Phospholipase C degraded the methylated phospholipids, but phosphatidyl-N,N-dimethylethanolamine appeared to be less accessible to the phospholipase. The phospholipid methylation activity was inhibited by the addition of S-adenosyl-L-homocysteine or by L-homocysteinethiolactone. When intact strips of rat aorta were incubated with L-[methyl-3H]methionine, [3H]methyl groups were incorporated into phospholipids. This incorporation was inhibited when L-homocysteinethiolactone was added to the incubation. Polarized fluorescence of diphenylhexatriene in aorta microsomes was measured to determine the apparent membrane fluidity. When intact strips of aorta were incubated with methionine or with L-homocysteinethiolactone, methionine enhanced and L-homocysteinethiolactone decreased apparent fluidity of the microsomal membranes. Phospholipid methylation activity was examined in aorta microsomes prepared from genetically spontaneous hypertensive SHR strain rats. Phospholipid methylation activity was substantially greater in the SHR aorta microsomes than in microsomes prepared from Wistar-Kyoto WKY control strain aorta. Membrane fluidity was greater in the SHR aorta microsomes than in the WKY aorta microsomes. The hypothesis that phospholipid methylation activity influences fluidity of membranes and the possible involvement of methylated phospholipids in aorta membrane functions are discussed.
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PMID:Methylation of phospholipids in microsomes of the rat aorta. 663 45

Inside-out vesicles (IOV) were prepared from human red blood cells. Steady-state uptake of 23Na was observed to generally follow an exponential time course with a rate constant of 1.57 +/- 0.09 h-1 (SE). One week of cold storage (0-4 degrees C) increased the rate constant to 2.50 +/- 0.12 h-1 (SE). Mg2+, Ca2+, or Sr2+ decreased the rate of 22Na uptake with no observable differences between the three divalent cations when tested at concentrations of 50 microM. Mg2+ was shown to decrease the rate of 22Na uptake at concentrations as low as 5 microM with maximal effect at 50 to 100 microM. The decrease in rate of 22Na uptake induced by Mg2+ could be enhanced by exposure of IOV to Mg2+ for longer periods of time. Trypsin treatment of OIV increased the rate of uptake of 22Na and was dependent on the concentration of trypsin added between 5 to 25 micrograms/ml (treated for 5 min at 25 degrees C). The ability of Mg2+ (50 microM) to decrease the rate of 22Na uptake was still observed after maximal trypsin treatment. Phospholipase A2 or phospholipase C treatment of IOV increased the rate of 22Na uptake and was dependent on the amount of phospholipase A2 (0.1 to 1.0 units/ml) or phospholipase C (0.25 to 2.5 units/ml) added (treated for 5 min at 25 degrees C). After phospholipase A2 treatment, the observed decrease in the rate of 22Na uptake induced by Mg2+ (50 microM) was generally greater than controls. After phospholipase C treatment, the observed decrease in rate of 22Na uptake induced by Mg2+ (50 microM) was less or absent when compared with controls. Phospholipase C treatment was less effective in preventing the Mg2+ effect the longer IOV were exposed to Mg2+. The results suggest that Mg2+ binds to phospholipid headgroups to reduce Na permeability perhaps by inducing a change in bilayer structure or phospholipid association.
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PMID:Effects of divalent cations, trypsin, and phospholipases on the passive permeability to sodium of inside-out vesicles from human red cells. 706 86


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