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)

Bovine adrenal tyrosine hydroxylase has been obtained in a form that is 85 to 90% pure. Sodium dodecyl sulfate-gel electrophoresis and density gradient centrifugation studies have established that the subunit molecular weight of the chymotrypsin-solubilized enzyme is 34,000. The presence of iron in the purified enzyme (0.50 to 0.75 mol of iron/mol of enzyme) has been established. Crude particulate tyrosine hydroxylase can be activated by the phospholipid, phosphatidyl-L-serine, or by exposure to enzymatic phosphorylating conditions. Both forms of activation lower the Km of the enzyme for its 2-amino-4-hydroxypteridine cofactor. By contrast, tyrosine hydroxylase that has been solubilized by chymotrypsin cannot be activated by either of these methods.
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PMID:Bovine adrenal tyrosine hydroxylase: purification and properties. 1 85

The complete amino acid sequence of the mangano superoxide dismutase from Escherichia coli B has been deduced through characterization of peptides from cyanogen bromide, bromonitrophenylsulfenyl skatole, citraconylated tryptic, and succinylated tryptic digests of the intact polypeptide chain and through subfragmentation of selected peptides with chymotrypsin, thermolysin, trypsin, and Staphylococcus aureus V8 extracellular protease. No significant homology is detected on comparison with the sequence of the copper- and zinc-containing superoxide dismutase from bovine erythrocytes, indicating that the manganese-iron and the copper-zinc classes of dismutases arose from independent evolutionary ancestors, a proposal previously based solely on enzymological and NH2-terminal sequence data. The amino acid sequence listed below corresponds to a molecular weight of 22,900 and appears to be identical in each subunit polypeptide of the native enzyme dimer. formula: (see text).
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PMID:The amino acid sequence of mangano superoxide dismutase from Escherichia coli B. 36 8

The effect of trypsin and chymotrypsin on antibacterial factors in bovine colostrum has been studied. Endogenous complement in colostrum was extremely sensitive to both enzymes. IgM was attacked by chymotrypsin but not by trypsin. Trypsin slowly attacked IgG1, causing loss of biological activity due to cleavage of both light and heavy chains. IgG1 was only very slightly attacked by chymotrypsin. Lactoferrin and transferrin in the iron-free state were both susceptible to proteolysis, but the iron saturated forms were more resistant and tended to give rise to stable iron-binding fragments.
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PMID:The effect of trypsin and chymotrypsin on the antibacterial activity of complement, antibodies, and lactoferrin and transferrin in bovine colostrum. 74 24

During the year 1974, 111 patients with urticaria were studied in the Department of Dermatology, of the Saint Paul's Hospital (Autonomous University of Barcelona). Among those, 77 had chronic urticaria, of which 22 a had low blood iron values. After iron treatment the urticaria improved or was cured in some of these patients. The remaining cases in which the cause of their hives was unknown were followed for one year. Some systemic causatives for their urticaria may appear on longer follow-up. At the same time, blood levels of salicylates trypsin and alpha-chymotrypsin were checked in 14 patients, with the object of a possible relationship concerning the persistence of the urticaria.
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PMID:[Chronic urticaria and serum iron]. 124 Oct 79

Soybean lipoxygenase 1 was studied using limited proteolysis and active-site labeling to begin the structural characterization of the enzyme in solution. The serine proteases trypsin and chymotrypsin cleaved the large monomeric protein (95 kDa) into two large polypeptides, a C-terminal fragment of about 30 kDa and an N-terminal fragment of about 60 kDa. Under conditions that led to complete cleavage of the protein as judged by SDS-polyacrylamide gel electrophoresis, the catalytic activity of the protein was either reduced slightly (chymotrypsin) or enhanced (trypsin). The characteristics of the cleaved enzymes were the same as for native lipoxygenase 1 in all aspects examined: insensitivity to cyanide, fluoride, and EDTA, regiochemical and stereochemical consequences of catalysis, and EPR spectroscopy upon oxidation by product. The two fragments apparently were tightly associated as they could not be resolved under conditions which preserved the catalytic activity. Both native and protease-cleaved lipoxygenase 1 formed covalent adducts when treated with either 14C-phenylhydrazine or 4-nitrophenylhydrazine. The label was found only in the 60-kDa fragment and following complete trypsin digestion was associated with a peptide beginning after Lys-482 in the primary sequence. Therefore labeling occurred in the vicinity of the conserved histidine cluster which has been postulated as the iron-binding site. From these observations it appears that lipoxygenase 1 exists as a pair of tightly associated domains with the iron-binding site located in the larger of the two.
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PMID:Limited proteolysis and active-site labeling studies of soybean lipoxygenase. 132 20

The ability of various reactive oxygen species and serine proteases to activate latent collagenase (matrix metalloproteinase-1) purified from human neutrophils was examined. Latent 70-75 kD human neutrophil collagenase (HNC) was efficiently activated by known non-proteolytic activators phenylmercuric chloride (an organomercurial compound) and gold thioglucose (Au(I)-salt). Corresponding degree of activation was achieved by reactive oxygen species including hypochlorous acid (HOCl), hydrogen peroxide (H2O2) and hydroxyl radical generated by hypoxanthine/xanthine oxidase (HX/XAO). The presence of trace amounts of iron and EDTA were necessary and even enhanced H2O2 induced activation of latent HNC. This activation could be abolished by an iron chelator desferrioxamine and a hydroxyl radical scavenger mannitol. HOCl induced activation of latent HNC was not affected by desferrioxamine and mannitol. Thus, these compounds do not inhibit the active/activated form of HNC. Latent HNC could also be activated by trypsin and chymotrypsin but not by plasmin and plasma kallikrein. The ability of mannitol and desferrioxamine to inhibit the H2O2-induced activation of HNC suggests the transition metal dependent Fenton reaction to be responsible for localized and/or site-specific generation of hydroxyl radical/hydroxyl radical -like oxidants to act as the activating oxygen species. Our results support the ability of myeloperoxidase derived HOCl to act as a direct oxidative activator of HNC and further suggest the existence of a new/alternative oxidative activation pathway of HNC involving hydroxyl radical.
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PMID:Activation of latent human neutrophil collagenase by reactive oxygen species and serine proteases. 217 13

Ferrochelatase from bovine kidney mitochondria has been purified 1600-fold with a 6.5% yield, exhibiting a specific activity of 490 nmol mesoheme formed/mg of protein per min. The Km values for mesoporphyrin IX and protoporphyrin IX with iron were 12.5 and 12.7 microM, respectively. The Km values for iron and zinc with mesoporphyrin IX were 3.51 and 3.17 microM, respectively. The purified enzyme showed a single band with an apparent molecular mass of 42,000 daltons (42 kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The rabbit antibody against the purified enzyme markedly inhibited activities of the enzyme from both the kidney and liver. Immunoblot analysis showed that the antibody reacted with the renal as well as the hepatic enzymes showing the same molecular weight. Peptide mapping with trypsin or alpha-chymotrypsin showed that digested peptides of renal enzyme were similar to those of hepatic enzyme. Ferrochelatase activity in mouse erythroleukemia (MEL) cells increased in parallel with an increase of heme synthesis by treatment with dimethylsulfoxide. Using immunoblotting techniques, the amount of the enzyme in the MEL cells has been shown to increase by the induction, showing a molecular mass of 41 kDa which was the same as that of the mouse hepatic enzyme. Comparative structural analysis of the enzyme of MEL cells and that of mouse liver by peptide mapping showed that the partial digestive peptides of both enzymes exhibited a similar pattern. These results strongly suggest that ferrochelatase in kidney, liver and erythroid cells can be of one type.
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PMID:Characterization of ferrochelatase in kidney and erythroleukemia cells. 231 Jul 48

Killing of rat pulmonary artery endothelial cells by activated polymorphonuclear leukocytes (PMNs), as measured at 4 hours, is catalase sensitive, iron dependent, and unaffected by addition of protease inhibitors. If the time course for exposure of endothelial cells to activated PMNs is extended to 18 hours, progressive injury occurs. Endothelial cell injury resulting at 18 hours is partially inhibited by catalase and partially inhibited by soybean trypsin inhibitor. Together, these two inhibitors function synergistically to protect the cells from injury. Exposure of endothelial cells to reagent H2O2 and purified proteolytic enzymes (trypsin, chymotrypsin, elastase, and cathepsin G) mimics the effects of activated PMNs: H2O2 alone is cytotoxic with maximal killing achieved by 4 hours; proteolytic enzymes produce cytotoxicity only at high concentrations and only after prolonged incubation (longer than 8 hours); and, in combination, H2O2 and proteolytic enzymes act synergistically. These data provide compelling evidence that PMN-mediated injury of endothelial cells involves interaction between oxygen products and proteases.
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PMID:Endothelial cell killing by neutrophils. Synergistic interaction of oxygen products and proteases. 267 21

The transferrin that is isolated from washed intestinal mucosal cell preparations consists partly of a fraction that has properties distinguishing it from serum transferrin. The serum transferrin contaminating mucosal preparations, even when fully saturated with iron and in the presence of proteinase inhibitors, also acquires the properties of the mucosal transferrin when the mucosa is homogenised. The mucosal transferrin is modified by a single cleavage of the polypeptide chain yielding a disulphide-linked peptide of 6550 daltons linked to the parent protein by a disulphide bridge. The amino-terminal sequence of the first 11 residues of this peptide could be aligned with both the known rat and human transferrin carboxy-terminal sequences. In both cases the sequence is preceded by a phenylalanine residue (residue 622 of human transferrin). This suggested that a mucosal chymotryptic enzyme was responsible even though rat transferrin is not susceptible to alpha-chymotrypsin if fully iron-saturated. Since transferrin mRNA is not found in the intestinal mucosa it must be imported from the serum. It remains uncertain whether the modified transferrin is present naturally and plays a role in iron absorption but these findings do indicate the eventual fate of any transferrin imported into an intestinal cell.
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PMID:Properties of the transferrin associated with rat intestinal mucosa. 304 65

The ferredoxin was purified from the green alga, Chlamydomonas reinhardtii. The protein showed typical absorption and circular dichroism spectra of a [2Fe-2S] ferredoxin. When compared with spinach ferredoxin, the C. reinhardtii protein was less effective in the catalysis of NADP+ photoreduction, but its activity was higher in the light activation of C. reinhardtii malate dehydrogenase (NADP). The complete amino acid sequence was determined by automated Edman degradation of the whole protein and of peptides obtained by trypsin and chymotrypsin digestions and by CNBr cleavage. The protein consists of 94 residues, with Tyr at both NH2 and COOH termini. The positions of the four cysteines binding the two iron atoms are similar to those found in other [2Fe-2S] ferredoxins. The primary structure of C. reinhardtii ferredoxin showed a great homology (about 80%) with ferredoxins from two other green algae.
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PMID:Purification, properties and complete amino acid sequence of the ferredoxin from a green alga, Chlamydomonas reinhardtii. 335 5


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