Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A preparation of peptidyl-tRNA from intact microsomes of mucin-synthesizing polysomes of sublingual salivary gland cells contained fatty-acylated galactosamine-free and galactosamine-enriched peptidyl-tRNA fractions, whereas trypsin-chymotrypsin treated microsomes yielded predominantly the acylated galactosamine-enriched peptidyl-tRNA complexes. Radioscanning and chemical analyses revealed that palmitate was substituted on all nascent peptides, except those shorter than 20 amino-acid residues. In contrast, the [35S]-methionine label was detected only on galactosamine-free peptides containing up to 70 amino acids. On SDS-polyacrylamide gel, the peptides released from galactosamine-enriched tRNA complexes separated into a multitude of bands ranging in size from 6000 to 60,000 dalton, whereas the total preparation afforded peptides ranging from 2000 to 60,000 dalton. Pulse-chase experiments, using radiolabelled methionine, palmitic acid and N-acetylgalactosamine, combined with chemical characterization of the radiolabelled fatty acids and carbohydrates from purified peptidyl-tRNA, confirmed that the N-terminal fatty acylation and the initial O-glycosylation with N-acetylgalactosamine are the co-translational processes taking place as soon as peptide is sufficiently large to be acylated, trimmed, and translocated to the luminal site of endoplasmic membrane.
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PMID:Co-translational processing and intracellular transport of rat salivary mucus glycoprotein. 325 86

1. The amount of sialoglycopeptide (SGP) mixture released from young (Y) erythrocytes by trypsin treatment was significantly larger than that from old (O) ones. 2. The two main membrane-surface sialoglycopeptides (Y-SGP and O-SGP) were isolated in yields of about 45% and 42% from the mixtures by a combination of Sephadex G-50 superfine gel filtration with DEAE-cellulose chromatography, respectively. Molecular weights of 12,000 and 12,100, respectively, were found for the Y-SGP and the O-SGP. 3. The Y-SGP showed a greater proportion of sialic acid than the O-SGP. The contents of galactose, N-acetylglucosamine and N-acetylgalactosamine of the Y-SGP were significantly lower than those of the O-SGP. 4. Both the SGPs exhibited the same reactivities against the MN reagents, but the reactivities against the lectins of Limulus polyphemus and Phaseolus vulgaris (E) were stronger in the Y-SGP than in the O-SGP. Neither the Y-SGP nor the O-SGP showed the reactivity to Arachis hypogaea (anti-T) lectin.
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PMID:Comparative study on the main membrane-surface sialoglycopeptides released from young and old human erythrocytes with trypsin. 335 36

The lectin Maclura pomifera agglutinin (MPA) binds to the apical surface of pulmonary alveolar type II but not type I cells. We show that MPA binds to a single membrane glycoprotein in type II cells with a molecular mass of 230 kDa in the rabbit and 200 kDa in the rat. The glycoprotein has an abundance of terminal N-acetylgalactosamine residues. It is a hydrophilic integral membrane protein suggesting that it has an extensive extramembrane domain or is an ion channel. The glycoprotein is similar in rat and rabbit, with the exception that the rat glycoprotein is partially sialylated and is trypsin sensitive. The MPA-binding glycoprotein represents a new integral membrane marker of the apical domain of the pulmonary alveolar type II cell.
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PMID:Identification and characterization of the pulmonary alveolar type II cell Maclura pomifera agglutinin-binding membrane glycoprotein. 341 17

The behaviour in vivo of tight and loose variants of murine melanoma cells is further characterized. In vitro clonal morphology is reproduced on a variety of substrates. Results suggest that repeated selection of loose cells can co-select for cells with high metastatic and colonization potentials. Measurement of cell motility shows that 1G3 (loose) cells are more motile than 1G8 (tight) which are restricted to movements within clonal boundaries. Studies of adhesive properties show that loose cells are more easily detached from the substrate with trypsin or EDTA and that both cell lines attach more quickly to monolayers of loose cells than to tight ones. No gross differences are found either in attachment rates to plastic and ECM or in aggregation and disaggregation rates. Analysis of the cell surface has not revealed any differences between 1G8 and 1G3 in the sialylation of terminal galactose and N-acetylgalactosamine residues or in neuraminidase releasable sialic acid. The binding patterns of iodinated lectins to SDS-PAGE separated proteins are similar for both lines except for one 85/90 KD protein which is more abundant in 1G3 than 1G8 cells after neuraminidase treatment. The results show enhanced differences in metastatic potential of tight and loose clones after selective cloning and that there may be important differences in motility and cell-substrate interactions.
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PMID:Morphological and metastatic murine melanoma variants: motility, adhesiveness, cell surface and in vivo properties. 342 20

We investigated the role of carbohydrates in the interaction of a B cell differentiation factor designated as B151-TRF2 derived from B151K12 T cell hybridoma with the corresponding receptor on B cells. Induction of polyclonal differentiation of unprimed B cells into IgM-secreting cells by B151-TRF2 was specifically inhibited by addition of N-acetyl-D-glucosamine (GlcNAc) but not by structurally unrelated monosaccharides such as D-galactose, D-glucose, and N-acetyl-D-galactosamine (GalNAc). Absorption of B151-TRF2 activity with spleen cells was specifically inhibited by the presence of GlcNAc. These results indicate that GlcNAc residues are involved in the interaction of B151-TRF2 with the receptor on B cells. To gain insight into mechanism by which GlcNAc inhibits B151-TRF2-mediated B cell responses, the existence of GlcNAc residues was examined on the B151-TRF2 molecule and the corresponding receptor on the B cell surface. The results revealed that B151-TRF2 molecule was not bound to various lectin-coupled agarose beads so far tested, suggesting absence of carbohydrate moieties on the B151-TRF2 molecule. By contrast, pretreatment of spleen cells with trypsin or glycosidase mixture abolished their ability to absorb B151-TRF2 activity. Moreover, B151-TRF2-absorbing ability of spleen cells disappeared by the pretreatment with beta-N-acetylglucosaminidase, which cleaves terminal GlcNAc. The fact that pnitrophenyl (PNP)-GlcNAc specifically inhibited such enzyme activity on target cells indicates that terminal GlcNAc on the B cell surface plays a crucial role in the interaction with B151-TRF2 molecule. Interestingly, it was also found that B151-TRF2 activity was trapped and eluted from GlcNAc-coupled agarose beads. Taken collectively, these results strongly suggest that B cell membrane receptors for B151-TRF2 comprise glycoproteins with a terminal GlcNAc residue(s), and that binding of B151-TRF2 with terminal GlcNAc on the receptor is important for the subsequent activation of B cells.
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PMID:Polyclonal B cell activation by a B cell differentiation factor, B151-TRF2. II. Evidence for interaction of B151-TRF2 with glycoprotein on B cell membrane via recognition of terminal N-acetyl-D-glucosamine residue(s). 348 78

We have carried out a comparative study of mature murine granulocytes with two immature haemopoietic cell lines (multipotential cells, FDCP-Mix, and granulocyte progenitor cells, FDCP-2) with respect to the structure and composition of their surface membrane glycopeptides. The glycopeptides were labelled biosynthetically by incubation of the cells for 1-3 days with [3H]glucosamine. Cell-associated glycopeptides were released by treatment with trypsin and the trypsin extract was exhaustively digested with Pronase to remove most residual peptide. Radiolabelled materials were fractionated by chromatography on lectin affinity columns connected in the series: lentil lectin (LCA), concanavalin A (Con A) and wheat germ agglutinin (WGA). Lectin-binding glycopeptides were eluted with appropriate competing sugars and further analysed by gel filtration, base/borohydride elimination and susceptibility to degradation by glycosidases including endo-beta-galactosidase. Abundant quantities of N-linked polylactosamine-type glycopeptides, which bound only to the WGA columns, were identified on mature granulocytes but the molecules were highly-branched (i.e. resistant to endo-beta-galactosidase). In contrast, there seemed to be very little branching in the polylactosamine chains from FDCP-2 cells, whilst corresponding carbohydrates from multipotential FDCP-Mix cells gave evidence for both linear and branched domains in the same, large complex glycans. O-Linked tetrasaccharides of general structure: NeuAc-Gal-(NeuAc)-GalNAc were found in clusters on WGA-binding glycopeptides from all cell types, these components being especially prominent on mature granulocytes. FDCP-2 cells were distinguished by the presence of monosialylated and non-sialylated counterparts of the foregoing tetrasaccharides. The relative amount of LCA-binding glycopeptides was low on FDCP-Mix cells by comparison with FDCP-2 cells and mature granulocytes. Our findings therefore demonstrate that notable differences in gross composition and molecular fine structure of surface membrane glycopeptides are detectable in haemopoietic cells at different stages of development. The relationship of these differences to the biological properties of cell surfaces remains to be established.
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PMID:Developmentally-related changes in surface membrane glycopeptides of murine haemopoietic cells. 359 80

Mucin glycopeptides were isolated from rat small intestinal mucosa after reduction/alkylation, trypsin digestion and gel chromatography. The oligosaccharides were released by using alkaline-NaBH4, separated into neutral and acidic species and permethylated. The derivatized mixtures were analysed with fast atom bombardment mass spectrometry and gas chromatography-mass spectrometry using thin film columns. Permethylated neutral oligosaccharides with up to seven sugars could be chromatographed and detected with mass spectrometry. The complex mixture revealed was partly due to the linkage GalNAc being substituted at both position 3 and 6. The approach will be very useful when analysing small amounts of mucins and mucin fragments.
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PMID:Rapid characterization of mucin oligosaccharides from rat small intestine with gas chromatography-mass spectrometry. 369 14

In the distal hypertrophic zone of growth-plate cartilage, the pericellular matrix surrounding individual chondrocytes and the territorial matrix uniting chondrocytes into columnar groups are invaded by metaphyseal endothelial cells prior to osteogenesis. In the present study, lectin-binding glycoconjugates were analyzed in these two matrix compartments of growth-plate cartilage from Yucatan swine. Nine lectin-fluorescein conjugates were tested by a postembedment method on 1-micron-thick, nondecalcified, Epon-embedded sections. Chondrocytes in all cellular zones were surrounded by a pericellular matrix which showed positive binding for peanut agglutinin (PNA), ricin agglutinin (RCA-I), and soybean agglutinin (SBA). Binding by these lectins was sensitive to digestion with hyaluronidase, chondroitinase, and trypsin. Pericellular glyconconjugtes that bind RCA-I and concanvalin A (CONA) after periodic acid oxidation, and which were sensitive to trypsin but not to chondroitinase or hyaluronidase, were present in the hypertrophic cell zone. Within the territorial matrix, binding of lectins specific for galactose, N-acetylgalactosamine, and fucose showed gradients of intensity which became maximal at the last transverse septum. Lectin-binding histochemistry more precisely differentiated the microheterogeneity of glycoconjugate distribution within these two matrix compartments than has been possible with other histochemical techniques. Lectin-binding affinity is a potentially useful technique by which to isolate cartilage matrix macromolecules unique to specific cellular zones of the growth plate.
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PMID:In situ localization of lectin-binding glycoconjugates in the matrix of growth-plate cartilage. 372 44

The major urinary trypsin inhibitor (Mr 44 000), isolated from human urine, contains 35% carbohydrate. In addition to N-acetylglucosamine and neutral sugars (primarily mannose and galactose), the carbohydrate moiety contains hexuronic acid and N-acetylgalactosamine and corresponds to a glycosaminoglycan. This carbohydrate chain is an integral component of the inhibitor: it does not dissociate from the inhibitor when using dissociative conditions such as sodium dodecyl sulfate, guanidinium chloride, or by increasing ionic strength or mixing with cetylpyridinium chloride. This glycosaminoglycan chain is sensitive to chondroitinase ABC or testicular hyaluronidase digestion and corresponds to slightly sulfated chondroitin 4-sulfate or 6-sulfate. After treatment by these enzymes, the urinary inhibitor has a lower molecular mass (Mr 26 000) but still inhibits trypsin.
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PMID:The major human urinary trypsin inhibitor is a proteoglycan. 373 76

The carbohydrate moieties of the glycocalyx of the retinal capillary endothelium were demonstrated using lectin-affinity cytochemistry. The endothelial surface was rich in sialic acid, N-acetylglucosamine, galactose and mannose. Low levels of N-acetylgalactosamine were present. There was no preferential distribution of lectin-receptor monosaccharides on the cell surface. The binding of all lectins was inhibited by the appropriate hapten sugars and by perfusion of trypsin or pronase prior to labeling. No differences were observed between vessels in the inner and outer retina.
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PMID:Identification of lectin-receptor monosaccharides on the endothelium of retinal capillaries. 375 49


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