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 photosensitive inactivation of trypsin and chymotrypsin by 4-fluoro-3-nitrophenyl azide (FNPA) is described. A dark inhibition was observed at elevated probe concentrations, and was reversible. The enzymes were stable to photolysis in the absence of probe. Photolytic inactivation of trypsin and chymotrypsin with FNPA was found to be irreversible, and occurs in minutes at concentrations of FNPA where dark inhibition is negligible. The photoprobe was equally effective at pH 3 or pH 8. Nonspecific inactivation appears to be low, as evidenced by the stability of glucose oxidase and peroxidase to photolysis with FNPA.
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PMID:Inactivation of trypsin and chymotrypsin with a photosensitive probe. 0 98

The relationship between activation of resting chick embryo fibroblasts by proteases and proteolytic alteration of the cell surface has been investigated. Five different proteases were examined: trypsin, collagenase, plasmin, alpha-chymotrypsin, and thrombin. All of these proteases, when added to the culture medium at concentrations of 0.08-2.2 mug/ml, stimulated deoxyglucose uptake and induced cell division. The absolute levels of stimulation depended on the specific protease. Activation ranged from a doubling in cell number in 24 hr for trypsin and thrombin down to a 47% increase in cell number for alpha-chymotrypsin. Except in the case of thrombin, the stimulatory effects of these proteases correlated with breakdown of Z, a protein which is the major chick surface protein as revealed by lactoperoxidase-catalyzed iodination and which disappears upon transformation. In the case of thrombin, stimulatory concentrations brought about no detectable loss of surface components. Thus loss of Z is not a necessary condition for activation of chick fibroblasts; it may be a sufficient condition for activation of part of the cell population.
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PMID:Effect of proteases on activation of resting chick embryo fibroblasts and on cell surface proteins. 17 Oct 80

Tunicamycin, an antibiotic which prevents the glycosylation of newly synthesized proteins, inhibits the replication of both vesicular stomatitis virus and Sindbis virus. In tunicamycin-treated infected cells, all of the viral proteins are synthesized but the glycoproteins are devoid of carbohydrate. The nonglycosylated glycoproteins could not be detected on the outside of the plasma membrane by lactoperoxidase labeling, indirect immunofluorescence staining, or chymotrypsin treatment of intact cells, whereas the glycosylated glycoproteins were readily detected by all three methods. These results indicate that the bulk of the nonglycosylated glycoproteins are unable to undergo the normal migration to the cell surface. In contrast to the normal glycosylated viral glycoproteins, the nonglycosylated glycoproteins were insoluble in nonionic detergents such as Triton X-100. The nonglycosylated glycoprotein of vesicular stomatitis virus could be solubilized using a combination of 6 M guanidine hydrochloride and 0.2% Triton X-100, but precipitated when the 6 M guanidine was removed by dialysis. These results suggest that the lack of carbohydrate alters the properties of the glycoproteins, which may explain their impaired mobility through the intracellular membranous system.
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PMID:Impaired intracellular migration and altered solubility of nonglycosylated glycoproteins of vesicular stomatitis virus and Sindbis virus. 20 Jun 26

1. Biopsies of rectal mucosa were obtained for histology and enzyme analysis from 32 patients with inflammatory and functional bowel disorders, and the biopsies were classified morphologically as active colitis, quiescent colitis or normal. 2. Supernatant fractions of biopsy homogenates were assayed for their content of the proteolytic enzymes alpha-chymotrypsin, elastase and cathepsin D, and of protein, unsaturated vitamin B12-binding capacity, lysozyme, myeloperoxidase and N-acetyl-beta-glucosaminidase. 3. Mean unsaturated vitamin B12-binding capacity was significantly raised above normal in the active colitic mucosa, and mean lysozyme activity was raised above normal in both active and quiescent mucosae. 4. In active colitic mucosa there was no rise above normal in mean activities of any of the proteolytic enzymes, though a significant fall below normal occurred in mean N-acetyl-beta-glucosaminidase activity in the active colitic group.
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PMID:Mucosal enzymes in human inflammatory bowel disease with reference to neutrophil granulocytes as mediators of tissue injury. 22 86

Mechanisms were studied that might explain the attachment and damage to Candida albicans pseudohyphae by neutrophils in the absence of serum. Attachment of neutrophils to pseudo hyphae was inhibited by Candida mannans (1-10 mg/ml), but not by mannose, dextran, chitin, conconavalin A, or highly charged polyamino acids. Contact was also inhibited by pretreatment of Candida before incubation with neutrophils with chymotrypsin, but not trypsin or several inhibitors of proteases. Similar results were obtained with pretreatment of neutrophils, except that trypsin was inhibitory. When pseudohyphae were killed with ultraviolet light, proteinpolysaccharide complexes of mol wt <10,000 were released which appeared to bind to the surfaces of neutrophils and inhibit contact between neutrophils and Candida, as well as other fungi. Damage to Candida by neutrophils was inhibited by agents known to act on neutrophil oxidative microbicidal mechanisms, including sodium cyanide, sodium azide, catalase, superoxide dismutase, and 1, 4 diazobicyclo (2, 2, 2) octane, a singlet oxygen quencher. Neutrophils from a patient with chronic granulomatous disease did not damage Candida at all. However, the hydroxyl radical scavengers mannitol and benzoate were not inhibitory. Cationic proteins and lactoferrin also did not appear to play a major role in this system. Low concentrations of lysozyme which did not damage Candida in isotonic buffer solutions damaged pseudohyphae in distilled water. Isolated neutrophil granules damaged pseudohyphae only with added hydrogen peroxide and halide, and damage occurred only with granule fractions known to contain myeloperoxidase. These findings suggest that neutrophils recognized a molecule on the Candida surface which has a chymotrypsin sensitive protein component, and which may be liberated from the cell surface upon death of organism. The neutrophil receptors for Candida appear to be sensitive to trypsin and chymotrypsin. Damage to Candida by neutrophils occurred primarily by oxidative mechanisms, including the production of superoxide and hydrogen peroxide interacting with myeloperoxidase and halide, as well as singlet oxygen, but did not appear to involve hydroxyl radical. Lysozyme might have an accessory role, under some conditions.
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PMID:Mechanisms of attachment of neutrophils to Candida albicans pseudohyphae in the absence of serum, and of subsequent damage to pseudohyphae by microbicidal processes of neutrophils in vitro. 34 Apr 71

1. Lysophospholipase activity solubilized from bovine liver microsomes could be precipitated for more than 80% by antibodies evoked in rabbits against the purified bovine liver lysophospholipase II. 2. After solubilization of the microsomes in 1.5% sodium deoxycholate, an immunoprecipitate containing lysophospholipase II in enzymically active form could be isolated. 3. Microsomal lysophospholipase activity was completely inhibited by [3H]diisopropylphosphofluoridate. Enzyme labelled in this way was isolated by immunoprecipitation from control and chymotrypsin-treated microsomes. Sodium dodecyl sulfate disc gel electrohporesis of the immunoprecipitates showed that chymotrypsin treatment of intact microsomes had no influence on the molecular weight of the enzyme. 4. Attempts to label the lysophospholipase II in microsomes by lactoperoxidase catalyzed iodination or by reaction with the diazonium salt of [125I]iodosulfanilic acid were negative, although both techniques labelled other microsomal proteins efficiently. 5. Antibody absorption experiments gave no indication for the presence of lysophospholipase antigenic sites on the outside surface of microsomes. 6. These experiments are interpreted to indicate that lysophospholipase II is exclusively located at the luminal side of the microsomal membrane.
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PMID:Studies on the transverse localization of lysophospholipase II in bovine liver microsomes by immunological techniques. 50 78

Lysosomal fraction was isolated from rat liver by density gradient centrifugation after pervious loading of lysosomes in vivo with Triton WR-1339. Tritosome preparations were incubated at 37 degrees C and pH 5 for 24 hr with purified human ceruloplasmin or haptoglobin. After this period approximately 20% of total alpha amino nitrogen was released from ceruloplasmin and over 40% from haptoglobin. This was accompanied by loss of peroxidase activity of haptoglobin (in complex with haemoglobin), while enzymatic activity of ceruloplasmin remained unaltered. Removal of sialic acid by neuraminidase had no effect on digestion of ceruloplasmin by rat liver tritosomes. Both glycoproteins were resistant to horse leucocyte proteinases and pancreatic eleastase but were easily inactivated by trypsin and chymotrypsin.
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PMID:Degradation and inactivation of ceruloplasmin and haptoglobin by rat liver lysosomes and some other proteinases. 65 34

The orientation of human erythrocyte membrane protein was examined by enzymic iodination using lactoperoxidase with the glucose-oxidase system for generating peroxide, followed by proteolytic digestion. The outer surface of intact cells was labeled with 125I and the cytoplasmic surface of either resealed ghosts containing lactoperoxidase or of inside-out vesicles was labeled with 131I. Following iodination, the outer surface (resealed ghosts) or the cytoplasmic surface (outer surface of inside-out vesicles) was digested with trypsin, chymotrypsin, or pronase. Sodium dodecyl sulfate gel electrophoresis of the isolated membranes revealed three major and several minor peaks of radioactivity. Their surface orientation, defined within the limits of the specificity of the probes used, was as follows: the three major peaks consist of: (a) a 90,000 to 100,000 molecular weight component labeled on both surfaces; its proteolytic digestion profile indicated that it spans the membrane in an asymmetric manner and that it is composed of more than one peptide; (b) the major red cell membrane glycoprotein (apparent molecular weight 60,000) which is labeled and digested at only the outer surface; and (c) peptide(s) of high molecular weight (approximately 200,000), labeled and digested at only the cytoplasmic surface. The minor components include a glycoprotein of approximately 25,000 (apparent molecular weight) accessible to both surfaces and peptides of 60,000 to 70,000, 45,000, and 20,000 molecular weight labeled only on the inner surface.
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PMID:Arrangement of human erythrocyte membrane proteins. 80 40

The orientation of proteins and glycoproteins of the platelet surface has been studied using various surface probes and labeling reagents. A fourth major glycoprotein has now been detected in platelet plasma membranes by sodium dodecyl sulfate-gel electrophoresis in addition to the previously recognized glycoproteins I, II, and III. Glycoprotein IV Mr, = approximately 87,000) appears to be present on the inner aspect of the membrane or buried within it since it is not accessible to surface probes such as lactoperoxidase-catalyzed iodination, radiolabeling with transglutaminase and [14C]glycine ethyl ester, or proteolytic enzymes. The ratio of these four major membrane-bound glycoproteins is approximately 10:4:2:3. Contrary to previous reports, only one glycoprotein, glycoprotein III, is accessible to lactoperoxidase-catalyzed iodination in intact platelets. Differences in the rate of destruction of glycoprotein II in intact platelets by trypsin suggests that two components may be migrating in this region. Examination of the soluble fraction obtained following platelet homogenization showed the presence of a single soluble glycoprotein of molecular weight 148,000 comprising about 10% of total platelet sialic acid. Treatment of intact platelets with neuraminidase resulted in the quantitative loss of siliac acid from the soluble glycoprotein, and it was strongly labeled in the intact platelet by [14C]glycine ethyl ester in the presence of transglutaminase. Treatment of intact platelets with chymotrypsin which does not cause the platelet release reaction, caused the rapid conversion of the soluble glycoprotein to a macroglycopeptide. These results indicate a surface origin for the soluble glycoprotein rather than a cytoplasmic or granular origin. The term glycocalicin is suggested for this glycoprotein in view of its origin in the platelet glycocalyx.
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PMID:Platelet glycocalicin. I. Orientation of glycoproteins of the human platelet surface. 82 54

The 95,000-dalton polypeptide in human red blood cell membranes constitutes about 25% of the membrane protein. Previous labeling studies have shown that different regions of this polypeptide are exposed to the inside and outside of the cell and have suggested a role for the protein in anion exchange across the membrane. This polypeptide has been fragmented by chymotrypsin digestion of intact red cells and by treatment of purified polypeptide with 2-nitro-5-thiocyanobenzoic acid, hydroxylamine, and N-bromosuccinimide. The sites of cleavage by each of these reagents have been located relative to the NH-2 and COOH-terminals of the intact 95,000-dalton polypeptide. Polypeptide obtained from cells labeled with 1-isothiocyanate-4-benzene [35S]sulfonic acid (an inhibitor of anion transport), 125I and lactoperoxidase, or 32P has been similarly fragmented and these labels have been assigned to specific regions of the polypeptide. There are at least two sites of phosphorylation of the polypeptide; the major sites lies within 10,000 daltons of the NH2-terminal requiring that this portion of the polypeptide lie inside the cell. Sites of chymotrypsin cleavage and 125I and lactoperoxidase labeling are in a 7,000-dalton region toward the COOH-terminal of the polypeptide; this region must lie outside the cell. Between these two regions the polypeptide must traverse the lipid bilayer an odd number of times. 1-Isothiocyanate-4-benzenesulfonic acid also labels the protein near the site of chymotrypsin cleavage.
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PMID:Fragmentation of the 95,000-dalton transmembrane polypeptide in human erythrocyte membranes. 95 79


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