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)

Two distinct groups of non-collagenous components were isolated from rat cortical bone gelatin which had previously been digested with purified bacterial collagenase. One component was disulfide-bonded, strongly acidic, trypsin-labile glycoprotein aggregate with a molecular mass of more than 100,000 daltons. When reduced with beta-mercaptoethanol this protein disaggregated into subunits with a molecular mass of about 60,000 daltons. The other components consisted of a group of polypeptides with a molecular mass of about 5,000 daltons. The latter group was present in collagenase digests prepared from normal bone gelatin but was hardly detectable or absent in digests of gelatin prepared from either autolyzed, trypsinized or lathyritic bone, or from the residue of neutral salt extracted rat tail tendon.
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PMID:Collagenase-released non-collagenous proteins of cortical bone matrix. 19 1

1. Confluent human skin fibroblasts maintained in a chemically defined medium incorporate l-[1-(3)H]fucose in a linear manner with time into non-diffusible macromolecules for up to 48h. Chromatographic analysis demonstrated that virtually all the macromolecule-associated (3)H was present as [(3)H]fucose. 2. Equilibrium CsCl-density-gradient centrifugation established that [(3)H]fucose-labelled macromolecules released into the medium were predominantly glycoproteins. Confirmation of this finding was provided by molecular-size analyses of the [(3)H]fucose-labelled material before and after trypsin digestion. 3. The [(3)H]fucose-labelled glycoproteins released into fibroblast culture medium were analysed by gel-filtration chromatography and sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. These techniques demonstrated that the major fucosylated glycoprotein had an apparent mol.wt. of 230000-250000; several minor labelled species were also detected. 4. Dual-labelling experiments with [(3)H]fucose and (14)C-labelled amino acids indicated that the major fucosylated glycoprotein was synthesized de novo by cultured fibroblasts. The non-collagenous nature of this glycoprotein was established by three independent methods. 5. Gel-filtration analysis before and after reduction with dithiothreitol showed that the major glycoprotein occurs as a disulphide-bonded dimer when analysed under denaturing conditions. Further experiments demonstrated that this glycoprotein was the predominant labelled species released into the medium when fibroblasts were incubated with [(35)S]cysteine. 6. The relationship between the major fucosylated glycoprotein and a glycoprotein, or group of glycoproteins, variously known as fibronectin, LETS protein, cell-surface protein etc., is discussed.
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PMID:Biosynthesis and release of glycoproteins by human skin fibroblasts in culture. 20 58

We have observed that treatment of rabbit synovial fibroblasts with proteolytic enzymes can induce secretion of collagenase (EC 3.4.24.7) and plasminogen activator (EC 3.4.21.-). Cells treated for 2-24 hr with plasmin, trypsin, chymotrypsin, pancreatic elastase, papain, bromelain, thermolysin, or alpha-protease but not with thrombin or neuraminidase secreted detectable amounts of collagenase within 16-48 hr. Treatment of fibroblasts with trypsin also induced secretion of plasminogen activator. Proteases initiated secretion of collagenase (up to 20 units per 10(6) cells per 24 hr) only when treatment produced decreased cell adhesion. Collagenase production did not depend on continued presence of proteolytic activity or on subsequent cell adhesion, spreading, or proliferation. Routine subculturing with crude trypsin also induced collagenase secretion by cells. Secretion of collagenase was prevented and normal spreading was obtained if the trypsinized cells were placed into medium containing fetal calf serum. Soybean trypsin inhibitor, alpha(1)-antitrypsin, bovine serum albumin, collagen, and fibronectin did not inhibit collagenase production. Although proteases that induced collagenase secretion also removed surface glycoprotein, the kinetics of induction of cell protease secretion were different from those for removal of fibronectin. Physiological inducers of secretion of collagenase and plasminogen activator by cells have not been identified. These results suggest that extracellular proteases in conjunction with plasma proteins may govern protease secretion by cells.
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PMID:Proteases induce secretion of collagenase and plasminogen activator by fibroblasts. 20 72

To explore the interaction of vesicular stomatitis virus (VSV) proteins with cellular membranes, we have isolated membranes from infected cells that have been radioactively pulse-labeled. We have found conditions of isolation that result in membrane preparation which contain primarily the VSV membrane protein (M) and glycoprotein (G). Both of these proteins are very firmly attached to membranes: conditions known to release peripherally associated membrane proteins from membranes (S. Razin, Biochim, Biophys. Acta 265:241-246, 1972; S. J. Singer, Annu. Rev. Biochem. 43:805-826, 1974; S. J. Singer and G. L. Nicholson, Science 175:720-731, 1972) are ineffective in detaching either the G or the M protein. The results of trypsin digestion of these membrane fractions suggest that the M protein resides primarily on one side, the cytoplasmic side of cellular membranes, whereas the glycoprotein has been transported to the lumen of the membrane vesicle. However, we present evidence that the glycoprotein is transmembranal and that approximately 3,000 daltons of one end of the molecule is on the cytoplasmic side of the membrane. We have also found that undenatured VSV M protein contains a trypsin-resistant core with a molecular weight of 22,000. This region of the M protein is trypsin-resistant regardless of its association with membranes.
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PMID:Assembly of viral membranes: nature of the association of vesicular stomatitis virus proteins to membranes. 20 19

Primary and secondary cultures of rhesus monkey kidney cells supported multiple-cycle replication of Sendai virus, but later passages lost this ability, and this was reflected in decreased plaque formation. Multiple-cycle replication also did not occur in LLC-MK2 cells, a continuous line of RMK cells. Failure of replication in serially passed cells was correlated with a decrease in proteolytic cleavage of a viral surface glycoprotein (Fo), and the ability of cells to support multiple-cycle replication and plaque formation could be restored by the addition of trypsin (0.3 microgram/ml) to the overlay medium. The use of wild-type virus, which requires trypsin, and protease activation mutants that require chymotrypsin or elastase for activation has provided evidence that the activating protease supplied by primary or secondary cells has trypsin-like activity. Inactive virus, with uncleaved Fo glycoprotein, absorbed to primary or secondary cells but did not infect them, even though such cells possess the enzyme that is capable of cleaving the Fo glycoprotein of virus synthesized in these cells. The inability of these cells to activate adsorbed virus indicates that the activating protease that they possess is inacessible to adsorbed virus, although it can act on the Fo glycoprotein during virus maturation in these cells. These data provide a biochemical explanation for the failure of later passages of a cell strain or a continuous cell line to support the replication of a paramyxovirus.
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PMID:Loss on serial passage of rhesus monkey kidney cells of proteolytic activity required for Sendai virus activation. 20 71

A protein, present in bovine seminal plasma, initiates forward motility in immature, immotile caput spermatozoa that have been incubated with a cyclic AMP phosphodiesterase inhibitor. An improved motility assay was developed to study this process and the protein involved. This forward motility protein exhibits multiple forms when fractionated on the basis of charge or molecular weight. Molecular sieving in urea or sodium dodecyl sulfate and dithiothreitol results in a single peak of activity which will re-form the larger aggregates in the absence of these agents. The molecular weight of this monomeric motility protein, as estimated from molecular sieving under these dissociating conditions, is 37,500. The forward motility protein can be partially purified by heat treatment, gell chromatography in urea, and affinity chromatography on concanavalin A/agarose. Enzymatic treatments further suggest a glycoprotein nature, i.e. treatment with beta-galactosidase, neuraminidase, alpha-mannosidase, or galactose oxidase reduces its activity by 50%; treatment with trypsin completely abolishes forward motility protein activity. On the basis of concurrent studies on the activity, properties, and distribution of forward motility protein in bovine body fluids, it is suggested that this protein is involved in the development of the capacity for motility as sperm traverse the epididymis.
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PMID:Bovine sperm forward motility protein. Partial purification and characterization. 21 Nov 30

The structural polypeptides of egg grown mumps virus were analysed by SDS-polyacrylamide-slab-gel electrophoresis. Mumps virions contained eight major polypeptides with mol. wt. of 75, 73, 71, 61, 47, 44, 42 and 40 X 10(3). The 75 K and 61 K polypeptides were glycosylated. In virions treated with pronase and trypsin, the 75 K glycoprotein was removed more readily from the virus than the 61 K glycoprotein. The gradual removal of the 75 K glycoprotein was paralleled by a decrease of haemagglutinating activity. The large glycoprotein was cleaved into a 40 K glycoprotein by trypsin treatment. Pronase and trypsin treatment also removed the smallest 40 K non-glycosylated polypeptide. Thus this polypeptide appears to be located on the outside of the virion and probably represents a cleavage product of the large glycoprotein. Treatment of virions with 2% Triton-X 100 under alkaline conditions in the absence or presence of 2 M-KCl solubilized the two glycoproteins and a fraction of the 71 and 44 K polypeptides, but not the 73 and 47 K polypeptides. The two smallest polypeptides were solubilized by treatment with 2% Triton X-100 in the presence of 2 M-KCl. Since the 40 K polypeptide was interpreted to represent a cleavage product of the large surface glycoprotein the 42 K polypeptide was proposed to represent the membrane protein of mumps virus. The 44 K polypeptide co-migrated with Vero cell actin. The nature of the 47 K polypeptide could not be determined, but it is probably located in the central part of the virus. The 73 K polypeptide and in some experiments also the 71 K polypeptide were found in purified nucleocapsid preparations. It is concluded that mumps virus has a general polypeptide composition similar to other paramyxoviruses. However, the molecular weights of the different polypeptides of mumps virus differ markedly from the corresponding polypeptides in Newcastle disease virus and Sendai virus.
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PMID:Structural polypeptides of mumps virus. 21 49

The binding of low density lipoprotein (LDL) to fibroblasts occurs through apolipoprotein B, a glycoprotein. The role of the carbohydrate in binding was assessed in two ways: (1) LDL, freed of sialic acid and most of the glucosamine and hexoses by digestion with a mixture of glycosidases, bound to fibroblasts as does native LDL. (2) The glycopeptides liberated from apoprotein B by trypsin and pronase failed to inhibit LDL binding to fibroblasts. Apparently the carbohydrate moiety of LDL does not interact with the plasma membrane receptor.
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PMID:The absence of a role for the carbohydrate moiety in the binding of apolipoprotein B to the low density lipoprotein receptor. 21 98

Comparisons of membrane glycopeptides from baby hamster kidney fibroblasts (BHK21/C13) and a clone transformed by Rous sarcoma virus (C13/B4) were made by using cells metabolically labeled with radioactive D-glucose and L-fucose. Most of the glycopeptides were metabolically labeled with both the general and the specific glycoprotein precursors. The glycopeptides obtained from the cell surface by controlled trypsinization were representative of the surface membrane as shown by comparing them with those of purified membrane preparations. The trypsin-removable glycopeptides from both cell types were further processed and examined by successive chromatography on Sephadex G-50 and DEAE-cellulose. The chromatographic distribution patterns showed that each cell type had glycopeptides of similar characteristics, although the proportions of the glycopeptides differed dramatically between the two cell types. After transformation there was an increase in the larger, more highly charged glycopeptides. This was verified by the increased sialic acid content in these glycopeptides. Some of the glycopeptides were homogeneous after the size and charge separations, since a variety of procedures did not separate them further. The apparent homogeneity and reasonably few species obtained may be due to the methods of isolation, with the procedures selecting particular glycopeptides from the external portion of the membrane. These results corroborate the concept and show for the first time that virus transformation is accompanied by an increase in certain species of glycopeptides rather than de novo synthesis.
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PMID:Membrane glycopeptides from virus-transformed hamster fibroblasts and the normal counterpart. 22 Oct 10

Parallel determinations were made, of 10 individual serum proteins and of proteins in the bronchial secretion obtained by aspiration from 8 subjects that did not show manifest bronchopulmonary disease. By application of the formula suggested by Deuschl and Johansson it was found that 37 percent of IgG, 84,5 percent of IgA, 48,9 percent of transferrins, 15,2 percent of alpha-1-anti-trypsin and 11,3 percent of ceruloplasmin present in the bronchial secretion are synthetised in the bronchial mucosa itself, while the rest occur as a result of diffusion from the blood. Acid alpha-1-glycoprotein and haptoglobin from the bronchial secretion originate in the blood. IgM was evidenced in the bronchial aspirate in only 3 subjects, and alpha-2 macroglobulin was not found in any of the subjects.
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PMID:[Studies of the proteins in normal bronchial secretion]. 22 41


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