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)

A surface coat of host serum proteins was detected on virulent Treponema pallidum by sodium dodecyl sulfate-gel electrophoresis. The loosely associated serum proteins could be removed by repeated washings in a protein-free medium. Washed T. pallidum retained the ability to readsorb numerous host proteins from rabbit serum as well as iodinated rabbit or human albumin. In addition, various avidly associated host serum proteins including albumin, alpha(2)-macroglobulin, transferrin, ceruloplasmin, immunoglobulin G, immunoglobulin M, and C3 were identified on the outer envelope of washed treponemes by an immunoadsorbent technique with protein A-bearing staphylococcus. Hyaluronidase treatment did not remove the avidly associated host proteins from the surface of washed treponemes, whereas trypsin treatment resulted in decreased levels of agglutination. Electrophoretic patterns of trypsin-treated treponemes showed that treponemal proteins as well as adsorbed host proteins were released concurrently by protease digestion. Reacquisition studies involving alpha(2)-macroglobulin and transferrin suggested the presence of noncompetitive binding sites for serum proteins on the treponemal outer envelope. Finally, differences among the T. pallidum preparations from individual rabbits with respect to incorporation of [(35)S]methionine, extent of agglutination with antisera, and length of time required for removal of avidly associated host proteins by trypsin treatment indicated biological variability among the treponemal populations.
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PMID:Surface-associated host proteins on virulent Treponema pallidum. 9 74

In order to elucidate the cytochemical properties of the membranous structure between enamel and ameloblasts of the rat incisor at the maturation stage, chromic phosphotungstic acid (Cr-PTA) and periodic acid-silver methenamine (PA-silver) techniques for electron microscopy were employed in combination with a digestion test with hyaluronidase, neuraminidase, collagenase or trypsin. Also, acid phosphatase activity of ameloblasts at the maturation stage was examined with a modified GOMORI's metal salt method. An intensely Cr-PTA reactive band approximately 0.1 micron thick appeared along the surface layer of enamel at the transitional stage, and at the very beginning of the maturation stage another intensely Cr-PTA reactive band which was seen by uran-lead stain to be a delicate electron-dense membranous structure appeared as well between enamel and ameloblasts. A lot of cytoplasmic small vesicles or tubular structures, both intensely reactive to Cr-PTA, were observed near the apical membranes of the overlying ameloblasts indicating that those organelles must have been responsible for the secretion of the latter band. Acid phosphatase activity was clearly demonstrated at Cr-PTA reactive large vesicles in the cytoplasm of those cells. The PA-silver staining technique manifested a band heavily deposited with silver grains along the surface layer of enamel, i.e., where the former band existed, but showed no particular reaction at the latter, the band-like layer between enamel and ameloblasts. Hyaluronidase or neuraminidase treatment remarkably decreased the Cr-PTA reaction of the latter band. Trypsin or collagenase treatment, on the other hand, not only eliminated the Cr-PTA reaction but digested the band itself. These results suggest that the membranous structure between enamel and ameloblasts of a rat incisor is not so-called enamel cuticle but a basal lamina produced by overlying ameloblasts and that the basal lamina contains collagenous components even though it lies on enamel.
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PMID:Cytochemical studies of ameloblasts and the surface layer of enamel of the rat incisor at the maturation stage. 21 3

Studies have been made on the effect of trypsin, chymotrypsin, pronase, lipases, hyaluronidase and digitonin on electrophysiological properties of the neurons of the snail H. pomatia under external application. Proteases and lipases gradually depolarize the neuronal membrane, decrease the amplitude and prevent the onset of action potentials, initially increase and then decrease the membrane resistance. The decrease in the membrane resistance coincides with the period of maximum inhibition of resting and action potentials in the neurons. The enzymes studied do not affect the membrane capacitance. Changes in electrophysiological characteristics induced by the enzymes are partially reversible provided the preparation is soaked in Ringer's solution for a sufficient time. Digitonin rapidly and irreversibly depolarizes the membrane, decreases its resistance and blocks action potentials. Hyaluronidase does not significantly affect neuronal electrophysiological properties when applied solely, but facilitates the development of changes during subsequent effect of proteases.
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PMID:[Effect of hydrolases and digitonin on the electrophysiological characteristics of the neurons of the snail, Helix pomatia]. 67 79

An experimental model of disc herniation in tail discs of rats is described. Constant result on nucleus hernia and intervertebral narrowing were obtained by an easy manipulation on numerous rats. Intradiscal injection of aprotinin produced a widening of the disc height. Trypsin, collagenase, chymopapain, and hyaluronidase induced a narrowing of disc height; trypsin induced macroscopic necrosis of the soft surrounding tissues; and collagenase had a destructive effect on nucleus pulposus, annulus fibrosus, and even on end-plates. Chymopapain and hyaluronidase acted mainly on nucleus pulposus. Hyaluronidase could be of interest as a nucleolytic drug and needs further studies on optimal dosage and lack of side effects in the surrounding tissues before injecting it into human discs.
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PMID:Experimental model of disc herniations in rats for study of nucleolytic drugs. 244 86

The length-tension properties of alveolar wall from normal cats were studied before and after exposure to enzymes naturally found in mammals (elastase, trypsin, collagenase, hyaluronidase). Hyaluronidase effected little change while all the proteolytic enzymes altered the mechanical properties of lung tissue. Collagenase removed the "mechanical stop" and the alveolar walls fractured at low forces. The properties of wall exposed to trypsin resembled those of elastase-treated tissue. Elastase increased the extension necessary to reach a given force and increased the maximum length (L(max)) and resting length (L(o)). Maximum extensibility (lambda(max)), the ratio of L(max) to L(o), fell with both elastase and trypsin digestion. A reduction in lambda(max) simulates the changes in alveolar wall properties seen in the lungs of the aged and in those with an irreversible diffuse obstructive pulmonary syndrome (DOPS(I)). Unlike these states, however, the energy loss in stretching alveolar wall increased with elastolysis. Furthermore, the changes in L(o) necessary to effect a change in lambda(max) of alveolar wall comparable to that seen in DOPS(I) were excessive. The altered tissue properties that occur in man with obstructive pulmonary syndromes could not be produced with these proteolytic enzymes or with hyaluronidase.
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PMID:Simulation of tissue properties in irreversible diffuse obstructive pulmonary syndromes. Enzyme digestion. 435 77

The molecules occurring as terminal residues on the external surfaces of nuclei prepared from rat liver by either sucrose-CaCl(2) or citric acid methods and nucleoli derived from the sucrose-CaCl(2) nuclei were studied chemically and electrokinetically. In 0.0145 M NaCl, 4.5% sorbitol, and 0.6 mM NaHCO(3) with pH 7.2 +/- 0.1 at 25 degrees C, the sucrose-CaCl(2) nuclei had an electrophoretic mobility of -1.92 microm/s/V/cm, the citric acid nuclei, -1.63 microm/s/V/cm, and the nucleoli, -2.53 microm/s/V/cm. The citric acid nuclei and the nucleoli contained no measurable sialic acid. The sucrose-CaCl(2) nuclei contained 0.7 nmol of sialic acid/mg nuclear protein; this was essentially located in the nuclear envelope. Treatment of these nuclei with 50 microg neuraminidase/mg protein resulted in release of 0.63 nmol of sialic acid/mg nuclear protein; treatment with 1 % trypsin caused release of 0.39 nmol of the sialic acid/mg nuclear protein. The pH-mobility curves for the particles indicated the sucrose-CaCl(2) nuclei surface had an acid-dissociable group of pK. approximately 2.7 while the pK for the nucleoli was considerably lower. Nucleoli treated with 50 microg neuraminidase/mg particle protein had a mobility of -2.53 microm/s/V/cm while sucrose-CaCl(2) nuclei similarly treated had a mobility of -1.41 microm/s/V/cm. Hyaluronidase at 50 microg/mg protein had no effect on nucleoli mobility but decreased the sucrose-CaCl(2) nuclei mobility to -1.79 microm/s/V/cm. Trypsin at 1 % elevated the electrophoretic mobility of the sucrose-CaCl(2) nuclei slightly but decreased the mobility of the nucleoli to -2.09 microm/s/V/cm. DNase at 50 microg/mg protein had no effect on the mobility of the isolated sucrose-CaCl(2) nuclei but decreased the electrophoretic mobility of the nucleoli to -1.21 microm/s/V/cm. RNase at 50 microg/mg protein also had no effect on the electrophoretic mobility of the sucrose-CaCl(2) nuclei but decreased the nucleoli mobility to -2.10 microm/s/V/cm. Concanavalin A at 50 microg/mg protein did not alter the nucleoli electrophoretic mobility but decreased the sucrose-CaCl(2) nuclei electrophoretic mobility to -1.64 microm/s/V/cm. The results are interpreted to mean that the sucrose-CaCl(2) nuclear external surface contains terminal sialic acid residues in trypsin-sensitive glycoproteins, contains small amounts of hyaluronic acid, is completely devoid of nucleic acids, and binds concanavalin A. The nucleolus surface is interpreted to contain a complex made up of protein, RNA, and primarily DNA, to be devoid of sialic acid and hyaluronic acid, and not to bind concanavalin A.
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PMID:Molecules at the external nuclear surface. Sialic acid of nuclear membranes and electrophoretic mobility of isolated nuclei and nucleoli. 476 32

Isolation of cells is nowadays performed by enzymatic means. The influence of such enzymes on the surface coat of mesenchymal and blastemal cells during the dissociation of limbs buds from 11-day-old mouse embryos was studied electron microscopically after staining with ruthenium red. EGTA or collagenase failed to bring about cell separation. The surface coat seemed to be unchanged after collagenase treatment. After EGTA an increase in extracellular filaments was observed. The proteases alpha-chymotrypsin, dispase II, papain, pronase P and trypsin (0.2%, 37 degrees C, 20 min) succeeded in completely dissociating limb buds. Apart from single granules, there was a detachment of the surface coat from the cells in all cases studied. Hyaluronidase led to only partial separation, but the detachment of the surface coat was almost complete, indicating a GAG-rich surface layer on these cells.
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PMID:Changes in the surface coat of mesenchymal cells of mouse limb buds after enzymatic cell separation. 626 Aug 88

Chick embryo fibroblasts constitute a useful model for investigating cell surface differentiation using Ricinus lectin as a marker. Fibroblasts from 8-day chick embryos had two classes of Ricinus lectin binding sites, whereas those from 16-day embryos displayed only one class. Hyaluronidase treatment of fibroblasts from 8-day embryos had no effect on their capacity to bind Ricinus lectin; however after this treatment, 16-day cells resembled 8-day cells since the former also exhibited two classes of lectin-binding sites. Treatment with hyaluronidase released 2-5 times more hyaluronic acid from the older cells than from the younger cells. The same hyaluronidase treatment did not change the number of 8-day cells detached by trypsin from the substrate, but increased the number of detached 16-day cells. These observations suggest (i) that the greater adhesiveness to the substrate of the 16-day cells might be due to the presence on the cell surface of a larger amount of glycosaminoglycans at 16 days than at 8 days, and (ii) that the increased accumulation of hyaluronic acid on the cell surface might be involved in an alteration in the cell membrane during differentiation.
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PMID:Inaccessibility of certain Ricinus lectin binding sites due to the increase in hyaluronic acid during chick embryo development. 668 62

The bones of the head and face of vertebrate embryos only form after their progenitor cells have undergone an inductive interaction with embryonic epithelia. We have investigated whether epithelial cell products can substitute for epithelia in allowing mandibular ectomesenchyme to form bone. Mandibular epithelia from embryonic chicks were cultured on Millipore filters for 28 days to allow them to deposit an extracellular matrix, shown by electron microscopy to be a basal lamina-like material. Mandibular ectomesenchymal cells formed bone when placed on to these epithelial extracellular products and grafted to chorioallantoic membranes of host embryos. Treatment of epithelial cultures with trypsin or L-azetidine-carboxylic acid removed both the extracellular products and their ability to induce bone formation. Hyaluronidase treatment did neither. We concluded that a proteinaceous component of epithelial basal lamina provides a sufficient inductive stimulus to initiate differentiation of bone within mandibular ectomesenchyme.
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PMID:Induction of bone by epithelial cell products. 711 72

The distribution of anionic microdomains has been described in cerebral vessels and more recently in capillaries of peripheral nerve. Evidence is accumulating that these sites play a role in the barrier function of vascular endothelia in the PNS and CNS. The chemical nature of anionic sites has been at least partly determined for cerebral vessels but not in peripheral nerve. This study reports our preliminary investigations to determine the nature of endothelial anionic sites in sciatic nerve. The effects of digestion of ultra-thin sections of nerve with a battery of proteolytic and glycolytic enzymes (papain, trypsin, proteinase K, hyaluronidase, heparinase, heparitinase and neuraminidase) on the distribution of anionic sites was determined using the label, cationic colloidal gold. Papain, a proteolytic enzyme of broad specificity, succeeded in removing the majority of cationic colloidal gold-binding sites on the luminal surface of vascular endothelia. In contrast trypsin and proteinase K were less effective, reflecting their narrower specificity. Hyaluronidase, heparinase and heparitinase did not significantly affect cationic colloidal gold-labelling. However, a considerable reduction in cationic colloidal gold-binding occurred following neuraminidase digestion. These results suggest that, as in cerebral vessels, sialic acid-containing glycoproteins are largely responsible for the negatively charged domains on the luminal membrane of endothelial cells in peripheral nerve.
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PMID:Molecular characterization of anionic sites on the luminal front of endoneurial capillaries in sciatic nerve. 817 16


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