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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Degradation of myelin basic protein during incubations with high concentrations of horseradish peroxidase has been demonstrated [Johnson & Cammer (1977) J. Histochem. Cytochem.25, 329-336]. Possible mechanisms for the interaction of the basic protein with peroxidase were investigated in the present study. Because the peroxidase samples previously observed to degrade basic protein were mixtures of isoenzymes, commercial preparations of the separated isoenzymes were tested, and all three degraded basic protein, but to various extents. Three other basic proteins, P(2) protein from peripheral nerve myelin, lysozyme and cytochrome c, were not degraded by horseradish peroxidase under the same conditions. Inhibitor studies suggested a minor peroxidatic component in the reaction. Therefore the peroxidatic reaction with basic protein was studied by using low concentrations of peroxidase along with H(2)O(2). Horseradish peroxidase plus H(2)O(2) caused the destruction of basic protein, a reaction inhibited by cyanide, azide, ferrocyanide, tyrosine, di-iodotyrosine and catalase. Lactoperoxidase plus H(2)O(2) and myoglobin plus H(2)O(2) were also effective in destroying the myelin basic protein. Low concentrations of horseradish peroxidase plus H(2)O(2) were not active against other basic proteins, but did destroy casein and fibrinogen. Although high concentrations of peroxidase alone degraded basic protein to low-molecular-weight products, suggesting the operation of a proteolytic enzyme contaminant in the absence of H(2)O(2), incubations with catalytic concentrations of peroxidase in the presence of H(2)O(2) converted basic protein into products with high molecular weights. Our data suggest a mechanism for the latter, peroxidatic, reaction where polymers would form by linking the tyrosine side chains in basic-protein molecules. These data show that the myelin basic protein is unusually susceptible to peroxidatic reactions.
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PMID:Proteolytic and peroxidatic reactions of commercial horseradish peroxidase with myelin basic protein. 7 59

Eight tests investigating the function of circulating polymorphonuclear leukocytes were performed in 68 subjects, half of whom smoked at least 20 cigarettes per day. Comparison of the two groups allowed determination of the in vivo effect of tobacco smoke on the nonspecific defense system of the body. Ingestion ability, oxygen consumption, and bactericidal activity were normal in smokers. Myeloperoxidase and neutrophil alkaline phosphatase activities also were unchanged. The nitroblue tetrazolium reduction and the serum lysozyme levels were slightly increased in smokers. The capillary tube random migration, though, was depressed, and intensive smoking further aggravated this change. It is suggested that tobacco smoke acts directly on one (or several) unidentified target site of polymorphonuclear leukocytes. This impairment, demonstrated in vivo, probably plays a role in the genesis of the bronchopulmonary diseases so frequent in heavy smokers.
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PMID:Effect of tobacco smoking on the functions of polymorphonuclear leukocytes. 22 75

The interaction of human polymorphonuclear neutrophilic leukocytes (neutrophils) with interleukin-1 (IL-1) resulted in a time- and concentration-dependent, selective, release of azurophil (myeloperoxidase, lysozyme) and specific (lysozyme, vitamin B12-binding protein) granule constituents. Myeloperoxidase (MPO) and lysozyme secretion was markedly attenuated if neutrophils were not exposed to cytochalasin B (CB) prior to contact with IL-1. Degranulation was significantly enhanced in the presence of extracellular calcium. IL-1-elicited granule exocytosis was inhibited by the intracellular calcium antagonist, 8-(N,N-diethylamino)-octyl-(3,4,5-trimethoxy) benzoate hydrochloride (TMB-8), a calmodulin antagonist, trifluoperazine (TFP), and an anion channel blocker, 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS). An evaluation of the role of arachidonic acid metabolites in IL-1-induced neutrophil activation revealed a suppressive effect on enzyme release exerted by the lipoxygenase inhibitors, piriprost potassium (6,9,deepoxy-6,9-(phenylimino)-delta 6,8 -prostaglandin I1, U-60,257B) and NDGA (nordihydroguaiaretic acid), and a cyclooxygenase/lipoxygenase inhibitor, ETYA (5,8,11,14-eicosatetraynoic acid). These data describe the characteristics of IL-1 as a human neutrophil secretagogue, and enhance our insight into the mechanism of inflammatory cell activation with this monokine.
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PMID:Interleukin-1 stimulates granule exocytosis from human neutrophils. 242 Jul 32

Myeloperoxidase (MPO)-deficient neutrophils (PMN) released considerably more beta-glucuronidase, lysozyme and vitamin B12-binding activities, when exposed to opsonized zymosan (STZ), than the normal counterpart. Release of the soluble enzyme lactate dehydrogenase was not appreciably changed over the incubation time with particles in either cell type. MPO-deficient PMN and normal PMN ingested STZ particles at a similar rate at early times, but thereafter phagocytosis by MPO-deficient PMN was significantly higher than that by normal PMN. The difference in degranulation between the two cell types greatly exceeded the difference in ingestion and was evident already at early phagocytosis times when no difference in phagocytosis was observed; this suggested that the higher degranulation in MPO-deficient PMN was at least in part independent of the increased ingestion. This was confirmed by experiments with the soluble stimulant N-formyl-L-norleucyl-L-leucyl-phenylalanine (FNLLP). MPO-deficient PMN and normal PMN exhibited a comparable respiratory burst when exposed to FNLLP plus cytochalasin B, but the defective cells released more azurophilic and specific granule markers than normal PMN. These results indicate that MPO-deficient PMN degranulate more than normal PMN and suggest a role for MPO in the regulation of degranulation.
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PMID:Increased degranulation of human myeloperoxidase-deficient polymorphonuclear leucocytes. 298 89

Myeloperoxidase synthesis during induction of differentiation of human promyelocytic leukemia HL-60 cells by 12-O-tetradecanoylphorbol-13-acetate (TPA) was studied. Differentiation was characterized by morphological changes, arrest of cell proliferation, development of cell adherence, and increased secretion of lysozyme. The cellular myeloperoxidase activity decreased early during induction of differentiation by TPA. Pulse-labeling experiments indicated that the rate of myeloperoxidase synthesis decreased to an undetectable level in cells exposed to TPA for 22 h. The relative amounts of myeloperoxidase mRNA in TPA-treated and untreated cells were determined by measuring translatable mRNA activity in a reticulocyte lysate system. Reduction in the myeloperoxidase mRNA level was observed as early as after 3 h treatment with TPA, and no myeloperoxidase mRNA was detected after 24 h. Time course experiments indicated that the time required for 50% reduction of myeloperoxidase mRNA in TPA-treated cells was approximately 5 h. These results suggest that TPA induces decrease of myeloperoxidase activity in HL-60 cells at a pretranslational level.
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PMID:Regulation of myeloperoxidase gene expression by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate in human leukemia HL-60 cells. 302 7

In the present investigation 11 females of normal constitution were subjected to a standardized fasting diet for 8 days. Three subjects dropped out early during the experimental period. Saliva and blood samples were collected before, during and after the fasting period. Serum analyses were made of some parameters often studied during undernutrition. As expected, values for creatinine and uric acid were increased. Secretion rate, pH, buffer capacity, electrolytes, total protein, carbohydrates, some antibacterial substances, the amount of Streptococcus mutans, total streptococci, and lactobacilli were determined in the saliva samples. The rate of plaque formation was also estimated. The effect of fasting on the measured parameters varied greatly among the individuals. Fasting caused a significant decrease in secretion rate, concentration of phosphate and sialic acid in stimulated whole saliva. There was no significant increase in concentration of any substance measured. The decrease of the ratio of sialic acid to protein indicates a disturbance of glycoprotein synthesis. In resting saliva the activity of a bacteria-aggregating glycoprotein appeared to be unchanged, whereas the decreases in thiocyanate concentration and lysozyme activity were statistically significant. Lactoperoxidase activities did not change significantly. The amount of IgA, IgG, IgM as well as the microbial counts showed no changes. The rate of plaque formation increased during fasting.
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PMID:Studies of the effect of diet on saliva secretion and caries development: the effect of fasting on saliva composition of female subjects. 620 45

During phagocytosis neutrophils from 8 patients with chronic granulomatous disease released 2-3 times more activity of lysozyme and beta-glucuronidase than did normal neutrophils. This difference was caused by the partial inactivation of these enzymes by normal neutrophils. The inactivation of granule enzymes depends on oxidative products and takes place mainly in the phagolysosomes. Myeloperoxidase is involved in this phenomenon.
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PMID:Oxidative damage to lysosomal enzymes in human phagocytosing neutrophils. 628 25

When exposed to zymosan or latex particles or heat-inactivated staphylococci, freshly prepared human blood monocytes and granulocytes rapidly released a large fraction of their lysozyme content. Within 24 hours the total lysozyme activity in the monocyte suspensions tripled, while it doubled in the granulocyte suspensions, indicating synthesis of the enzyme following release. The monocytes in particular seemed to release and synthesize lysozyme without any other stimulus than contact with lymphocytes and the tube walls. Potassium caseinate in solution did not influence the lysozyme release. Myeloperoxidase and beta-glucuronidase, which in the granulocytes are kept in lysosomal fractions separate from most of the lysozyme, were neither released nor synthesized to a significant degree. Moreover, the minute amount of lactate dehydrogenase released indicated that the lysozyme release was not the result of cell lysis. Accordingly, the monocytes, which are not already stimulated by adherence to nonphagocytosable surfaces, are capable of selective enzyme release similar to that of the granulocytes.
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PMID:In vitro release of lysozyme from monocytes and granulocytes. 632 67

Myeloperoxidase of neutrophilic leukocytes (MPO) at pH 4.0 to 6.5 mediated oxidation of Cl- ions, yielding hypochloride (OCl-) which then reacted with amino acids and polypeptides. Thiol and thioether groups may be oxidized to disulfide or to sulphoxides and sulphonic acids respectively. Tryptophanyl residues yielded 2-oxoindole. Epsilon amino groups of lysine produced chloramine which, however, decomposed, yielding aldehyde residues. Bovine serum albumin treated with MPO-Cl-H2O2 system yielded derivatives with a decreased affinity to antialbumin antibodies and increased electrophoretic mobility. Albumin aldehyde derivatives were also obtained. At H2O2 molar ratio with albumin 20:1, a precipitation of albumin occurred, due to the formation of new polymeric albumin derivatives. The lysozyme (LZM) lost its enzyme activity when 1.4 to 1.8 mol of H2O2 per 1 mol of LZM was used. Addition of H2O2 above molar ratio 5:1 produced LZM polymerization to di-, tri-, tetra and pentameric derivatives. IgA exposed to the MPO-Cl-H2O2-Cl- system split into light chains (molecular weight: 25.8 kDa), heavy chains (molecular weight: 81.8 kDa) and a third polypeptide which size was half the light chain size (molecular weight: 13.9 kDa). The IgA exceeding the HOCl ratio 1:350 (mg/mumol) produced both precipitation and degradation of the IgA polypeptide structure. The treatment of IgG with HOCl released a fragment corresponding to half the light chain size, the light chain, and the heavy chain, whereas HOCl treatment of IgM released only a fragment which size was smaller than the heavy chain and another fragment which size was the same as the light chain. The MPO-Cl-H2O2 system produced many specific changes in protein structures.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Oxidative modification of protein structures under the action of myeloperoxidase and the hydrogen peroxide and chloride system. 785 48

Eight patients with homozygous sickle cell anemia, 15 heterozygotes, and eight control individuals were investigated with respect to plasma concentrations of the inflammatory markers lysozyme and myeloperoxidase and the complement activation marker C3d. The patients showed significantly increased levels of myeloperoxidase and C3d, but not lysozyme, compared with the heterozygotes and the controls. The heterozygotes were also significantly different from the controls with regard to C3d concentration. The concentrations of myeloperoxidase and C3d in plasma showed a significant inverse correlation with the hemoglobin concentration. Myeloperoxidase and C3d showed a significant positive correlation. This suggests a role for the neutrophil and the complement system in the pathophysiology of sickle cell disease.
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PMID:Increased in vivo activation of neutrophils and complement in sickle cell disease. 827 46


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