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:3.4.21.1 (chymotrypsin)
10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Optimum conditions were determined for solubilizing cell membrane receptors for binding measles virus (MV). Evidence for specific receptors was shown from the saturability of MV binding to intact Vero cells or African Green Monkey erythrocytes (MRBCs). Receptors, solubilized from Vero cells and MRBC with 1.5% octyl glucoside, inhibited MV attachment, infectivity, and hemagglutination activities. Extracts from chicken erythrocytes, which did not bind MV, were inactive in all assays. MV binding activity in Vero or MRBC extracts was stable to heating (100 degrees, 10 min) or neuraminidase treatment, but was inactivated by a range of proteases, including chymotrypsin, and bound to lentil and pea lectin agaroses, to indicate a glycoprotein component.
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PMID:Characterization of octyl glucoside-solubilized cell membrane receptors for binding measles virus. 267 66

Different kinds of interactions involved in the properties of ovomucin gel formation from hen egg white were studied by combining physical and biochemical methods. A decrease in viscosity of the ovomucin gel was observed when it was subjected to chymotrypsin or sonication treatment. The viscosity decrease correlated with a change from non-Newtonian to Newtonian properties of the ovomucin gel. By treatment of the gel with either 5 M guanidinium HCl, 6 M urea, or 5% sodium dodecyl sulfate a change from non-Newtonian to Newtonian properties was also obtained. Although high ionic strength or sialic acid liberation from the ovomucin gel by neuraminidase treatment provoked a decrease in viscosity, it was not followed by a change in non-Newtonian properties. The results obtained suggest that different noncovalent interactions might be involved in gel formation. Electrostatic interactions (partially destroyed by sialic acid removal or 2 M NaCl) and hydrophobic interactions might be responsible for protein-mucin and mucin-mucin interactions. Other bonds susceptible to chymotrypsin treatment and sonication would be involved in the interaction between mucin subunits.
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PMID:Interactions involved in ovomucin gel-forming properties: a rheological-biochemical approach. 270 76

When red cells (RBCs) are treated with papain, one form of the U antigen, which we have named UPS (U papain-sensitive), is almost completely removed or denatured. A second form, UPR (U papain-resistant), remains unaltered on the treated RBCs. Tests on 42 examples of anti-U showed that two contained only anti-UPS, 19 contained only -UPR, and 21 contained separable -UPS and -UPR. In those sera containing both antibodies, anti-UPR was always the stronger of the two. These findings suggest 1) that UPS is located on the Ss sialoglycoprotein (glycophorin B) at a position distal to a papain-sensitive site or that the cleavage point is within the portion of the SGP that comprises UPS, and 2) that UPR is located between the papain-sensitive site and the RBC membrane. The UPS determinant was not denatured by neuraminidase, L-cysteine, trypsin, ficin, or alpha-chymotrypsin, and it was only partially denatured by pronase. The finding that RBCs treated with para-chloromercuribenzoic acid or para-chloromercuriphenyl sulfonic acid did not react with anti-UPR but did continue to react with anti-UPS suggests that the in situ configuration of UPR, but not UPS, is dependent on the presence of one or more disulfide bonds. RBCs of the S-s-U+(weak) phenotype were shown to carry markedly reduced amounts of both UPS and UPR.
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PMID:Heterogeneity of anti-U demonstrable by the use of papain-treated red cells. 274 73

Ghosts were prepared from erythrocytes positive for the rare blood group antigen Pta. Immunoblotting of the solubilised ghosts with anti-Pta located the antigen on a band with an Mr of 31,600, about 1,100 higher than that of sialoglycoprotein gamma. Binding to the same band was also observed when cytoskeleton preparations from Pt(a+) erythrocytes were immunoblotted with the antibody. Haemagglutination and immunoblotting experiments were consistent in demonstrating that the Pta antigen is not inactivated by treatment of intact erythrocytes with neuraminidase or trypsin but is destroyed by treatment with alpha-chymotrypsin, papain or pronase. The data indicate that the Pta antigen is carried on a 'new' erythrocyte membrane protein.
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PMID:Partial characterisation of the human erythrocyte antigen Pta. 275 91

A reverse hemagglutination assay was used to study adherence to human erythrocytes by Escherichia coli H10407, which possesses colonization factor antigen I. Pretreatment of erythrocytes with trypsin, chymotrypsin, papain, protease, and neuraminidase completely abolished attachment reactivity. In addition, the hemagglutination reaction was prevented by the presence of urea and guanidine. In contrast, the lipases, nucleotide hydrolases, exoglycosidases, and reagents affecting disulfide or sulfhydryl moieties did not alter receptor reactivity. Glycoconjugates containing sialic acid inhibited the hemagglutination reaction. Furthermore, a sialoglycoprotein isolated from the erythrocyte membrane inhibited the hemagglutination reaction. Collectively, these data indicate that the erythrocyte receptor responsible for attachment by E. coli possessing colonization factor antigen I is a sialoglycoconjugate.
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PMID:Indications that the erythrocyte receptor involved in enterotoxigenic Escherichia coli attachment is a sialoglycoconjugate. 286 Dec 12

Phenylalanine accumulation in mucosal strips isolated from rat small intestine was significantly inhibited (P less than 0.01) after preincubation with trypsin, chymotrypsin, phospholipase D and neuraminidase. Unidirectional phenylalanine influx across the small intestine was significantly reduced (P less than 0.01) when the mucosal strips were preincubated with the above mentioned enzymes. Intestinal cell water and volume were not significantly changed (P greater than 0.6) when the intestinal tissues were preincubated with these enzymes.
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PMID:Effect of enzymatic digestion on phenylalanine transport across the small intestine. 286 66

The phenomenon of glioma killing by lymphokine activated killer cells (LAK) was studied. We demonstrate that LAK cells generated by culturing the lymphokine interleukin-2 (IL-2) with peripheral blood lymphocytes from brain tumour patients destroys autologous glioma. The rat 9L glioma model was used to show that LAK killing was tumour-selective as glioma but not syngeneic normal brain tissue was destroyed. The susceptibility of both human and 9L rat glioma to LAK cell killing was markedly diminished by pretreating glioma cells with trypsin or chymotrypsin, but was unaffected by pretreatment with neuraminidase, glycosidases, sodium periodate or hydrocortisone. These results suggest that the cell surface determinant on glioma cells responsible for its tumour selective lysis by LAK is a protein sensitive to trypsin and chymotrypsin. The tumour-selective killing of glioma by LAK in vitro prompted the initiation of a Phase I study in which ten patients with malignant glioma have been treated with direct intracerebral injection of IL-2 or LAK without evidence of systemic or brain toxicity.
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PMID:Interleukin-2 and lymphokine activated killer (LAK) cells in the treatment of malignant glioma: clinical and experimental studies. 287 9

Human sperm-free seminal plasma (HSP) contains inhibitors (I) of the seminal plasma histone kinase activity (HK). One I is dialyzable and the other I is nondialyzable and precipitable by dialysis of HSP against a hypotonic buffer. When the nondialyzable, precipitable I fraction is resolubilized, it inhibits HK in a concentration-dependent manner. Sephadex G-25 column chromatography of whole HSP resolves I in both the void (Vo) and inclusion (Vi) volumes. Rechromatography of the VoI resolves I solely in the Vo. These and other data suggest that the ViI does not originate from the VoI, and that both I activities represent separate molecular entities. VoI was further characterized and found to be heat labile, trypsin and neuraminidase insensitive, and alpha-chymotrypsin sensitive. VoI is not soluble in CHCl3 or CHCl3:CH3OH (2:1) and is not adsorbed by charcoal. Chromatography of VoI on Sephadex G-100 yields a broad peak of I that migrates just past the Vo. VoI has no detectable cyclic AMP (cAMP) binding activity and VoI activity is not affected by coincubation of VoI and HK with cAMP. VoI also does not bind to zinc-chelate or phenothiazine affinity columns. These data suggest that VoI is protein in nature with properties distinct from the class of previously described protein kinase inhibitors. Although the identity of VoI is not known, it does not appear to be the regulatory subunit of a cAMP-dependent protein kinase, calsemin or a zinc binding protein.
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PMID:Characterization of a seminal plasma-associated inhibitor of human seminal plasma protein kinase. 298 35

Human alveolar macrophages (AM) were obtained from eight normal volunteers using fiberoptic bronchoscopic lavage to explore potential interrelationships among leukocytes in pulmonary defense against infection. AM placed in monolayer tissue cultures released material into culture supernatants with the capacity to enhance the bactericidal capacity of human neutrophils. Neutrophils preexposed to supernatants killed Pseudomonas aeruginosa from 70 to 90% more efficiently than control cells (P less than 0.02). AM culture supernatants contained this material by 4 h of incubation, and in vitro stimulation of AM cultures with heat-killed P. aeruginosa further increased its production. Gel filtration of AM culture supernatants with a G-50 Sephadex column allowed isolation of a 6,000-D neutrophil-activating factor (NAF) that was resistant to heat (56 degrees C, 30 min). The isoelectric point of NAF, as determined by chromatofocusing, was approximately 7.6. Enzyme digestion of NAF specimens, prepared sequentially by gel filtration and chromatofocusing, demonstrated 50-70% loss of activity after incubations with trypsin, chymotrypsin, and neuraminidase. NAF was only minimally chemotactic and eluted from Sephadex G-50 with particles of a different molecular size than those of AM-derived chemotactic factors (i.e., approximately 10,000 D and less than 500 D). Preincubation of neutrophils with NAF resulted in greater release of superoxide anion upon their subsequent stimulation by either bacterial phagocytosis or by phorbol myristate acetate, as compared with control neutrophils stimulated in a like manner. These studies indicate that human AM secrete a heat-stable, low molecular weight basic protein, with the capacity to enhance oxidative microbicidal activity of neutrophils.
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PMID:Isolation and partial characterization of a human alveolar macrophage-derived neutrophil-activating factor. 298 53

A cell surface antigen (gp140) was previously shown to exist on T cell subsets as well as on monocytes and macrophages in normal peripheral blood. Elevated expression of this antigen was associated with immune system disorders, acute lymphocytic leukemias, and in vitro activation of T cells. The antigen could be identified with monoclonal antibody (MAb) T305. Gp140 was a biosynthetic product of T cells because it could be labeled with [3H]leucine or [3H] glucosamine. Biochemical studies of gp140 used high performance liquid chromatography with nitrocellulose blotting to isolate aliquots suitable for 125I radiolabeling and immunoprecipitation to demonstrate: a) a reduction in m.w. of gp140 KD to 90 KD after deglycosylation by trifluoromethanesulfonic acid, b) alteration of isoelectric point from 4.1 to 5.7 after neuraminidase treatments, c) absence of N-linked sugars based on resistance to endoglycosidase F, d) resistance to trypsin and chymotrypsin digestion but susceptibility to pronase, and e) presence of sialic acid and lactosaminoglycan as O-linked sugars. Gp140 could be labeled with the periodate/NaB[3H]4 technique, indicating its similarity to a class of sialoglycoproteins previously described on activated T-cells in mouse and man. The antigenic epitope recognized by MAb T305 contains sialic acid linked (2----3) to galactose; however, periodate oxidation of the exocyclic ring of sialic acid did not affect binding by MAb T305. In an attempt to determine the functional role of gp140, we tested the ability of MAb T305 to block: a) proliferation of peripheral blood lymphocytes to mitogens, b) response to interleukin 2 (IL 2) of an IL 2 dependent T cell line, and c) growth of a T-ALL derived cell line. No inhibition of proliferation or growth was noted. Although the function of gp140 remains unknown, its association with lymphocyte activation and certain disease states suggests that it may provide a target for modulation of the immune response. These studies characterize the structural features of gp140 and further define the epitope recognized by MAb T305.
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PMID:Characterization of a membrane surface glycoprotein associated with T-cell activation. 298 44


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