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)

Treatment of liver plasma membranes with trypsin at low concentrations (1 to 2 microgram/mg of protein) caused at 3- to 4-fold increase in alpha-specific [3H]epinephrine binding. The change was due to an increase in the number of high affinity binding sites, with no change in the dissociation constant. With increasing trypsin concentrations, the dissociation constant was decreased and there was a progressive loss of binding. Elastase, papain, and thermolysin caused similar effects, whereas the thrombin, leucine aminopeptidase, phospholipase A2, phospholipase C, phospholipase D, and detergents did not cause an increase in [EH]epinephrine binding. The increase in epinephrine high affinity binding sites was correlated with a loss of high affinity [3H]-dihydroergocryptine binding sites which also bind [3H]epinephrine with low affinity (El-Refai, M. F., Blackmore, P. F., and Exton, J. H. (1979) J. Biol. Chem. 254, 4375-4386). Incubation of membranes with the alpha blockers dihydroergocryptine (50 nM) and phenoxybenzamine (20 nM) prior to protease treatment diminished the increase in [3H]epinephrine binding induced by trypsin (1.5 microgram/mg). The concentration dependence and time course of trypsin actions on 70 nM [3H]epinephrine binding and 10 nM [3H]dihydroergocryptine binding are consistent with a trypsin-mediated conversion of low affinity epinephrine binding sites to high affinity epinephrine binding sites.
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PMID:Effects of trypsin on binding of [3H]epinephrine and [3H]-dihydroergocryptine to rat liver plasma membranes. Evidence for interconversion of binding sites. 624 49

Giant-cell formation induced by macrophage fusion factor (MFF) was not altered after pretreatment of macrophages with trypsin, chymotrypsin, pronase, neuraminidase, phospholipase C, or phospholipase D. Pretreatment of macrophages with either alpha-mannosidase or alpha-glucosidase completely inhibited giant-cell development, without altering macrophage viability. No alteration of giant-cell formation was observed when 0.1 M of L-fucose, N-acetyl-glucosamine, D-arabinose, D-xylose, melibiose, D-glucose, D-galactose, alpha-lactose, sucrose, D-fructose, or maltose was present during incubation of macrophages with MFF. Giant-cell formation was abolished when 0.1 M alpha-D-mannose was present during macrophage incubation with MFF. These results suggest that the protein moiety of MFF recognizes a specific receptor site on the macrophage membrane, one that is different from those described for other lymphokines and contains alpha-mannose.
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PMID:Chemical nature of the interaction between macrophage fusion factor and macrophage membranes. 635 71

The binding of human 125I-labeled lactoferrin (LF) to a population of adherent mononuclear cells (ADMC) and nonrosetting lymphocytes (E-) was abolished by prior treatment of the cells with deoxyribonuclease (DNase), but not ribonuclease (RNase). When DNase-treated ADMC were incubated with exogenous DNA, the binding of 125I-LF was restored. Enzymatic digestion with other enzymes, trypsin, phospholipase D, and neuraminidase, did not significantly influence 125I-LF binding. Saturable binding of LF at 0 degrees C was demonstrated for both E- and ADMC, with equilibrium dissociated constants of 0.76 x 10(-6) M and 1.8 x 10(-6) M, respectively. E- cells bound 2.5 x 10(7) and ADMC bound 3.3 x 10(7) molecules of Lf at saturation. Cell membranes were isolated from ADMC, E- and E+ and reacted with 125I-labeled LF; significant binding was only seen with ADMC and E-. Prior treatment of the membranes with DNase abolished the binding. Immunofluorescence studies indicated that a population of ADMC and E-, but not E+, exhibited a peripheral staining pattern for LF. Prior treatment of ADMC and E- with DNase abolished the surface immunofluorescence. This study provides evidence that cell membrane DNA acts as a binding site for exogenous LF. This is a novel role for DNA that has not been previously reported. Furthermore, it points to a basic difference between E+ cells vs. ADMC and E- cells in respect to their possession of cell surface DNA.
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PMID:Lactoferrin binds to cell membrane DNA. Association of surface DNA with an enriched population of B cells and monocytes. 660 Jul 47

The 125I-labeled S-100 specific binding to a Triton X-100 (TX-100) extract of synaptosomal particulate fractions (SYN) was investigated. The results indicate that (a) S-100 binding to the TX-100 extract is partially irreversible after a critical association time at 37 degrees C, while it is fully reversible after any association time at 4 degrees C; (b) trypsin and phospholipase C partially reverse the S-100 binding, while phospholipase D enhances the interaction to some extent, in a dose-dependent way; (c) EDTA and high concentrations of NaCl or KCl are more efficient as inhibitors of the S-100 binding to the TX-100 extract than as 125I-labeled S-100 dissociating agents, in analogy with previous observations with SYN; and (d) two main populations of solubilized S-100 binding sites can be evidenced by gel filtration and sucrose gradient centrifugation when low amounts of the TX-100 extract are processed and/or low S-100 concentrations are used, while two additional molecular species are separated when greater amounts of either factors are tested. These results suggest the possibility that S-100 may be involved in the regulation of some membrane activities.
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PMID:Biochemical and physicochemical properties of the solubilized S-100 protein binding activity of synaptosomal particulate fractions. 667 Dec 2

The electrokinetic behavior of red cell membrane vesicles of normal (ROV) and inverted (IOV) sidedness has been characterized using the laser Doppler technique of electrophoretic light scattering (ELS). At neutral pH ROV have a (approx. 25%) higher electrophoretic mobility than IOV and the two peaks can be resolved in the ELS spectrum to provide a quantitative estimate of the IOV/ROV ratio which is consistent with the ratio determined by assay of the activity of acetylcholinesterase. The ROV peak coincides with the mobility of fresh red blood cells and of resealed ghosts. Neuraminidase treatment reduces the ROV mobility by a factor of 2.6, while the IOV peak is reduced only slightly (less than 5%). Treatment with trypsin results in a single narrow ELS peak at about 60% of the mobility of ROV. Treatment of IOV with phospholipase C leaves the electrophoretic mobility unaltered, whereas treatment with phospholipase D increases their mode mobility by 22%. The mobility titration curve of IOV from pH 2 to pH 10 reveals three distinct inflection points which may be assigned to chemical groups on the cytoplasmic surface of the red cell membrane.
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PMID:Electrokinetic behavior of inside-out vesicles from human red cell membranes. 711 10

When a single cell suspension of human adult marrow or fetal liver is treated briefly with trypsin, the number of erythroid bursts arising in culture is significantly increased. Erythroid colonies show less stimulation. The time to reach maximum burst number may also be shortened. The absolute increase in burst number is greater at higher concentrations of erythropoietin, suggesting a synergistic effect of trypsin treatment with that of erythropoietin. Trypsin also increases the size of the individual burst subunit. The trypsin effect is not limited to a given class of bursts as distinguished by subunit number. Other enzymes, pronase, chymotrypsin and phospholipase D, also increase burst number but to a lesser degree. The burst-stimulating effect of trypsin is enzymatic since it is completely prevented by DFP, a specific inhibitor of trypsin action.
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PMID:Trypsin enhances erythropoiesis in vitro. 740 Jun 71

Parathyroid hypertensive factor (PHF) has been purified from two sources of material: plasma of spontaneously hypertensive rats (SHRs) and culture medium from organ culture of SHR parathyroid glands. Chromatographic characteristics of PHF from these two sources are identical. Biological activity of PHF (assayed as the characteristic delayed hypertensive response in normotensive rats) is sensitive to degradation by treatment in base, and the enzymes trypsin, chymotrypsin, phospholipase C, and phospholipase D. PHF activity may also be extracted from source material with chloroform: methanol (4:1). A hypothetical structure for the active component of PHF is suggested. This is comprised of a peptide liked to a lysophospholipid.
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PMID:Purification and structural characterization of parathyroid hypertensive factor. 751 47

A factor capable of deforming erythrocyte membranes, found in the culture supernatants of Bartonella bacilliformis, was purified 1840-fold using hydrophobic, ion exchange and gel exclusion chromatography. The final fractions contained a single detectable polypeptide species, referred to as deformin, having a molecular weight of 67000 by SDS-PAGE and a native molecular weight of 130,000 by gel exclusion chromatography or velocity sedimentation in a glycerol gradient. Erythrocytes treated with deformin acquire trenches, indentations, and invaginations which could be reversed by vanadate, dilauroylphosphatidylcholine (DLPC), or by raising the internal Ca2+ concentrations with the inophore A23187. Internal vacuoles also form. Erythrocytes treated with trypsin or neuraminidase are much more sensitive to deformin than untreated erythrocytes; erythrocytes treated with phospholipase D are less sensitive to deformin. This protein may play a role in causing the severe anemia which can result as a consequence of infection by B. bacilliformis.
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PMID:Purification of deformin, an extracellular protein synthesized by Bartonella bacilliformis which causes deformation of erythrocyte membranes. 769 92

Purified budded virions of Autographa californica nuclear polyhedrosis virus (AcNPV) contain abundant amounts of free ubiquitin, which has an altered electrophoretic mobility on SDS gels as compared with standard ubiquitin. Phase extraction of virion proteins with Triton X-114 indicated that the modified form of ubiquitin behaved as an integral membrane protein. The membrane-bound form of ubiquitin was labeled with both phosphate and palmitate, and its electrophoretic mobility was altered by treatment with phospholipase A2 and a phosphatidylcholine-specific phospholipase D. Mild trypsin digestion indicated that the acyl group was not linked to the C-terminus of the protein. Acylated ubiquitin could not be radiolabeled with a membrane-impermeable Bolton-Hunter reagent unless virus was pretreated with detergent. Together, these experiments suggest that ubiquitin is attached to the inner face of the viral membrane by a novel type of phospholipid anchor.
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PMID:Ubiquitin is attached to membranes of baculovirus particles by a novel type of phospholipid anchor. 783 50

It has been suggested previously that small amounts of the mature 115-kDa form of phosphatidylinositol (PtdIns)-glycan-specific phospholipase D from bovine serum may exist as a 47-kDa form which can also be generated in vitro by treatment with proteases. In this study, we investigated the possible proteolytic processing by trypsin of partially purified PtdIns-glycan- specific phospholipase D from bovine serum and found that tryptic digestion caused an apparent activation of the enzyme when assayed in the presence of 0.1% (mass/vol.) Triton X-100. Trypsin cleaved the 115-kDa form of PtdIns-glycan-specific phospholipase D into three major polypeptides with molecular masses of 33, 39, and 47 kDa. Under non-denaturing conditions, the polypeptides remained tightly but noncovalently associated with each other. However, in the presence of 6 M urea, the polypeptides could be separated by anion-exchange chromatography. After renaturation, PtdIns-glycan-specific phospholipase D activity was found to be associated with a 39-kDa fragment. Based on its size and its amino acid sequence, the active-site-containing fragment consisted of approximately 275 residues of the N-terminal region of PtdIns-glycan-specific phospholipase D. The active 39-kDa fragment hydrolyzed the PtdIns-glycan-anchors of solubilized acetylcholinesterase from bovine erythrocytes and variant surface glycoprotein from blood stream trypanosomes. However, this fragment was inactive on membrane-associated acetylcholinesterase and PtdIns.
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PMID:Generation by limited proteolysis of a catalytically active 39-kDa protein from the 115-kDa form of phosphatidylinositol-glycan-specific phospholipase D from bovine serum. 792 7


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