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)

The murine monoclonal antibody (MAb) designated DF3 has defined a high m.w. antigen detectable in human breast carcinomas and in human milk. DF3 antigen is detectable on apical borders of secretory mammary epithelial cells and in the cytosol of less differentiated malignant cells. DF3 antigen expression has been shown to correlate with the degree of human breast tumor differentiation, and the detection of a cross-reactive species in human milk has suggested that DF3 antigen might be useful as a biochemical marker of differentiated mammary epithelial cells. To further characterize DF3 antigen, we have developed an approach to purify the cross-reactive species by using gel filtration and antibody affinity chromatography. The affinity column-purified DF3 antigen was absorbed by wheat germ agglutinin and peanut agglutinin, but not by concanavalin A or lentil lectin. In contrast, wheat germ agglutinin inhibited MAb DF3 reactivity with the purified antigen, whereas there was little, if any, inhibition when using peanut agglutinin. These findings are thus consistent with the involvement of terminal N-acetyl-D-neuraminic acid and/or N-acetylglucosamine residues in the antigenic site. DF3 antigenicity was also sensitive to neuraminidase, but not chondroitinase ABC, chondroitinase AC, chondroitin-4-sulfatase, or hyaluronidase. Furthermore, DF3 antigen was sensitive to Pronase, subtilisin BPN', and alpha-chymotrypsin. The presence of O-glycosidic linkages between carbohydrate and protein in the DF3 antigenic site was further supported by the presence of NaBH4-sensitive sites. Together, these results suggest that sialyl oligosaccharides present on a peptide backbone are required for maintaining DF3 antigenicity. Similar findings have been demonstrated for DF3 antigen purified from both human milk and breast cancer effusions. However, the DF3 antigen in human milk consisted of a single high m.w. species, whereas the tumor-associated antigen consisted of two distinct glycoproteins with m.w. of 330,000 and 450,000. These findings may be relevant to the recent demonstration that distinct high m.w. DF3 antigens are elevated in the circulation of patients with breast carcinoma.
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PMID:Purification and characterization of a high molecular weight glycoprotein detectable in human milk and breast carcinomas. 404 99

The platelet binding properties of human monoclonal lupus autoantibodies have been studied. These IgM autoantibodies, produced by human X human hybridomas derived from lymphocytes of patients with systemic lupus erythematosus, are known to bind to single-stranded DNA. Four anti-DNA antibodies that express the dominant 16/6 idiotype--HF2-1/17, HF2-18/2, HF2-1/13b, and HF3-16/6--bound to glutaraldehyde-fixed platelets. In contrast, HF6-21/28, HF9-11/3, and polyclonal IgM bound poorly to platelets. [35S]Methionine was incorporated into HF2-1/17, and the interaction of the intrinsically radiolabeled HF2-1/17 with fixed platelets was evaluated in a solution phase radioimmunoassay. [35S]Methionine HF2-1/17 bound to fixed platelets and could be displaced by equivalent amounts of HF2-1/17, HF2-18/2, HF2-1/13b, and HF3-16/6. HF2-1/17 bound with greater affinity to fresh platelets and to thrombin-activated platelets than to glutaraldehyde-fixed platelets. Single-stranded DNA competed with platelets for the HF2-1/17 combining site. Treatment of fresh platelets with nuclease I, trypsin, chymotrypsin, and neuraminidase did not alter the binding of antibody to the platelet surface. No binding of antibody to phospholipid micelles was observed. Purified IgM autoantibodies did not inhibit platelet aggregation induced with ADP, thrombin, or ristocetin in platelet-rich plasma. These results indicate that the human IgM monoclonal anti-DNA autoantibodies that express the dominant 16/6 idiotype are polyspecific, bind to platelets, and interact with a platelet epitope that does not appear to involve DNA, protein, or sialic acid. These antibodies interact with platelets through the same sites responsible for antibody-DNA binding.
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PMID:Platelet binding properties of monoclonal lupus autoantibodies produced by human hybridomas. 406 19

Lower respiratory tract and systemic cell-mediated immunity have been studied in rabbits after infection with Listeria monocytogenes or Diplococcus pneumoniae. Respiratory tract cell-mediated immunity was evaluated by direct and indirect assays of migration inhibitory factor (MIF) production. Systemic delayed hypersensitivity was determined by means of intradermal testing with appropriate antigens. Aerosol exposure to listeria was followed by markedly increased numbers of free lower respiratory tract cells. These cells manifested antigen-stimulated inhibition of migration (mean inhibition of migration = 30.4%). Pneumococcal pneumonia was associated with similar but less dramatic changes. Intravenous administration of organisms was uncommonly followed by inhibition of lower respiratory tract cells in direct migration assays. Fractionated MIF, as well as crude supernates of antigen-stimulated lower respiratory tract and lymph node lymphocytes from animals exposed to listeria aerosols, caused inhibition of normal alveolar macrophage migration. MIF, produced by lymph node lymphocytes, has a molecular weight of approximately 65,000 and is inactivated by chymotrypsin or neuraminidase. Delayed dermal hypersensitivity to listeria antigen was observed in 54 of 55 animals exposed to listeria aerosols and in all 9 animals infected by the intravenous route. Delayed dermal reactions to pneumococcal sonicate antigen (but not capsular polysaccharide) followed D. pneumoniae respiratory tract infection in 19 of 28 animals, and was elicited in 5 of 6 animals after intravenous infection. Both local (macrophage migration inhibition) and systemic delayed hypersensitivity followed bacterial infection of the lower respiratory tract. MIF activity was shown to be one mechanism for inhibition of alveolar macrophage migration.
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PMID:Cell-mediated immunity after bacterial infection of the lower respiratory tract. 415 73

Influenza B/LEE/40, B/Rome/1/67, B/Hong Kong/8/73, and B/Victoria/98926/70 viruses have a similar polypeptide composition as analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. These viruses are composed of six or seven polypeptides, depending on whether one or two high-molecular-weight polypeptides are resolved, ranging in molecular weights from 27,000 to 90,400. Three of these polypeptides, namely the heavy and light hemagglutinin chains and the neuraminidase, have attached carbohydrate. Highly purified influenza B/LEE/40 and B/Rome/1/67 virus preparations have RNA-dependent RNA polymerase activity equivalent to the incorporation of 100 and 30 pmol, respectively, of (3)H-UMP per mg of virus protein per h at 37 C, which is demonstrated only in detergent-treated virus suspensions. However, no RNA-dependent DNA polymerase enzyme activity was detected in the two viruses although virus suspensions were "activated" by heat, alpha-chymotrypsin, and detergents. Other enzymatic activities were associated with purified preparations of influenza B virus and were attributed to minor contamination of virus with host cell enzymes. Thus, nucleoside and deoxynucleoside phosphohydrolase enzymes were active in the absence of detergents and catalyzed the release of 1,200 and 1,800 nmol of P(i) per mg of virus protein in 30 min at 37 C from ATP and dATP substrates. Thin-layer chromatography indicated that the products of the phosphohydrolase enzymes of influenza B/LEE/40 were mainly nucleoside diphosphate and monophosphate. The latter enzymes were tightly bound to influenza B/LEE/40 virus and could not be removed completely by repeated centrifugation, including centrifugation of the virus to equilibrium in density gradients of 25 to 40% (wt/vol) cesium chloride. A low degree of RNase (approximately 0.01 mug% contamination) and phosphatase (10-30 nmol of P(i) released per mg of virus protein per 30 min) activity was detected in some, but not all, influenza B/LEE/40 virus preparations.
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PMID:Polypeptide composition of Influenza B viruses and enzymes associated with the purified virus particles. 435 55

the absorption of vitamin B(12) in many animals requires its prior association with intrinsic factor (IF) and attachment to a specific receptor in the intestine. Employing Triton X-100, we have solubilized from guinea pig ileum a factor that binds intrinsic factor-vitamin B(12) complex (IF-B(12)). This binding factor was soluble to the extent that it was not sedimented by centrifugation at 100,000 g for 1 h and was small enough to enter the included volume of a Sepharose 4-B column. Furthermore, the ileal extract contained no microfine particles of membrane upon electron microscopic search. When a portion of the extract was incubated with a mixture of gastric juice and (57)Co-labeled vitamin B(12), a portion of the radioactivity was excluded from a Sephadex G-200 column. When gastric juice from a patient with a congenital abnormality of IF that prevented its binding to intestine was substituted for normal human gastric juice, radioactivity was not excluded from the gel, indicating failure of this abnormal IF-B(12) to bind to the intestinal extract. These data suggested the presence of a specific binder of IF-B(12) in the ileal mucosal extract. The reactions of normal IF-B(12) with the solubilized binding factor and with the membrane-bound "receptor" had several characteristics in common, including calcium dependence, temperature independence, and pH optimum near neutral. Extracts from the distal intestine showed more activity than did those from the proximal. The solubilized binding facter seemed specific for IF-B(12) in that it was not blocked by prior incubation with excesses of either free vitamin B(12) or IF. Binding activity of the extract was decreased by incubation at pH 2.0, by heating to 56 degrees C, and by incubation with chymotrypsin and dithiothretiol. Incubation with trypsin, neuraminidase, and sulphydryl blockers did not affect it. The Triton X-100 extract of guinea pig ileal mucosa contains a specific binding factor that probably is the receptor for IF-B(12). This appears to be a protein with function dependent on peptide and disulphide linkages.
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PMID:Solubilized receptor for intrinsic factor-Vitamin B12 complex from guinea pig intestinal mucosa. 485 16

Purified virions of HVJ (Sendai virus) were found to contain a guanylate cyclase activity that converts GTP to cyclic GMP. Activities of adenylate cyclase and 5'-nucleotidase which are frequently used as marker enzymes of cell membranes were not detected in the virus. Guanylate cyclase and virion-associated activities, neuraminidase and hemagglutinin, were co-purified during a purification of virions. Guanylate cyclase activity was not detected without disruption of the virions with a detergent, Triton X-100 or Nonident P-40. Treatment of intact HVJ with a proteolytic enzyme, trypsin or chymotrypsin, destroyed both neuraminidase and hemagglutinin; however, most of the guanylate cyclase ws retained. Guanylate cyclase activity was found in fractions containing nucleocapsids after sucrose density gradient centrifugation of disrupted virions. These results indicated that the enzyme was tightly bound to cores of HVJ and, therefore, its presence could not be explained by binding of host cell enzyme to the surface of virions. Properties of the virus-derived enzyme and particulate fractions of host cell homogenates were similar. Antiserum against nucleocapsids of HVJ inhibited guanylate cyclase activity of HVJ and particulate fractions of cells such as chorioallantoic membrane and rat liver, while soluble guanylate cyclase was not inhibited by antiserum. The biological significance and origin of guanylate cyclase found in HVJ are obscure and await further study.
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PMID:Evidence for guanylate cyclase activity associated with hemagglutinating virus of Japan (Sendai virus). 610 29

A macromolecule has been partially purified which influences the choice of the neurotransmitter synthesized by sympathetic neurons. Previous studies showed that culture medium conditioned by incubation on certain types of non-neuronal cells increased [3H]acetylcholine synthesis and accumulation from [3H]choline in primary cultures of neurons dissociated from neonatal rat superior cervical ganglion and grown in the virtual absence of non-neuronal cells. A concomitant decrease of [3H]catecholamines production was observed (Patterson, P. H., and Chun, L. L. Y. (1977) Dev. Biol. 56, 263-280). The active cholinergic factor in conditioned medium from C6 glioma or primary rat heart cultures has been purified about 1500-fold by a sequence of ammonium sulfate precipitation, DEAE-, CM-cellulose, and Sephadex G-100 chromatography. The partially purified factor is active at 1 microgram of protein/ml of culture medium and is eluted from Sephadex columns as a single peak of apparent Mr = 40,000-45,000. This material is insensitive to 0.2 M 2-mercaptoethanol, but is inactivated by 1 mM Na periodate. Its activity is partially decreased by treatment with a protease from Streptomyces griseus but is unaffected by neuraminidase. Material purified through the ammonium sulfate, DEAE- and CM-cellulose steps contains large amounts of trypsin- and chymotrypsin-inhibiting activities.
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PMID:A diffusible factor responsible for the determination of cholinergic functions in cultured sympathetic neurons. Partial purification and characterization. 611 Jun 68

This paper reports the isolation and characterization of a soluble antigen shared by the liver and kidney of human and some other animal species. Homogenates of human liver in saline were centrifugated at 27,000 g and the supernatants were fractionated by preparative polyacrylamide gel electrophoresis. The gels were divided in sections and each was injected into rabbits; after absorption with polymerized normal human serum, the antiserum obtained by injecting one of the sections reacted only with saline extracts of human liver and kidney when tested against a variety of human tissue extracts. The absorbed antiserum, polymerized and insolubilized with glutaraldehyde, was used to purify the antigen by affinity chromatography. The purified antigen proved to be a glycoprotein containing 19 percent carbohydrate, had a molecular weight of 5.8-6.0 x 10(4) Daltons and a pI of 7.2-7.4. The antigen, relatively thermostable, was precipitated by 35-55 percent ammonium sulphate; its antigenic activity was not affected by extraction with 0.6 N perchloric acid or by incubation with ribonuclease, deoxyribonuclease or neuraminidase but was destroyed by incubation with ttypsin or chymotrypsin. Immunoperoxidase studies showed that the antigen appeared concentrated in the neclei of liver and kidney glomerular epithelial and tubular epithelial cells in humans and rats. The antigen could not be detected in human hepatomas or hypernephromas or in the rat Morris hepatoma 5123.
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PMID:Isolation and characterization of a human liver and kidney-specific protein: the hepato-renal (H-R) antigen. 615 31

It has been shown that HLA-B27 lymphocytes from healthy individuals (B27+ ankylosing spondylitis [AS]-), which are not lysed by an antiserum against Klebsiella K43, can be rendered susceptible to lysis after incubation in the culture filtrate of Klebsiella K43. This finding is compatible with a specific modification by a Klebsiella K43-derived soluble factor of a B27-associated lymphoid cell component. Preliminary characterization of the factor has indicated that it is nondialyzable, but it is heat labile at 56 degrees C for 30 min and has a 35,000-50,000 mol wt. The modifying factor activity of the filtrate is destroyed by neuraminidase but not by trypsin and alpha-chymotrypsin. Furthermore, the ability of the factor to convert B27+AS- lymphocytes can be specifically absorbed by B27+AS- lymphocytes, but not by B27+AS+, B27-AS+, or by B27-AS- lymphocytes, which suggests that B27+AS- cells carry a hypothetical receptor which can specifically bind a Klebsiella K43 antigenic determinant. These results imply that the modification by environmental agents of specific major histocompatibility complex-associated gene products may be an important element in the pathogenesis of the HLA-B27-linked seronegative arthropathies.
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PMID:Characterization of a factor(s) present in Klebsiella culture filtrates that specifically modifies an HLA-B27-associated cell-surface component. 615 68

Macrophage cytotoxicity factor (MCF) was purified in 3 consecutive steps including adsorption chromatography on Matrex Gel Red A, hydrophobic chromatography on phenylalanine-Sepharose, and isoelectric focusing. MCF was characterized as a protein with a m.w. of approximately 30,000 by gel filtration on Sephadex G-100 with 2 isoelectric points at 7.4 and 8.4 in the presence of urea. The unpurified supernatant was fairly stable provided that manipulations favoring adsorption to membrane materials used for dialysis or ultrafiltration were omitted. The partially purified preparation was highly unstable. Trypsin treatment did not affect MCF activity, whereas chymotrypsin destroyed it. Treatment with glycosidases and neuraminidase or cultivation of cells in the presence of 2-deoxy-D-glucose or tunicamycin did not impair the MCF activity. MCF was separated from migration inhibitory factor (MIF) by 2 methods: first, isoelectric focusing in the presence of urea, and second by gel filtration on Ultrogel. MCF could be separated from interferon by chromatography on poly(I)-Sepharose.
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PMID:Partial purification and chemical characterization of macrophage cytotoxicity factor (MCF, MAF) and its separation from migration inhibitory factor (MIF). 616 71


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