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

---

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

The localization of D-lactate dehydrogenase in membrane vesicles prepared from Escherichia coli was studied using antibody against the purified enzyme. The activity of D-lactate dehydrogenase and D-lactate-dependent oxygen uptake of membrane vesicles prepared by using a French press were completely inhibited by this antibody, suggesting that the enzyme is localized on the outside of these vesicles. This and previous results (Futai, 1974) strongly indicate the inversion of these vesicles. The D-lactate dehydrogenase and D-lactate-dependent oxygen uptake of membrane vesicles prepared by treatment with ethylenediaminetetraacetate-lysozyme were inhibited about 15% by the antibody, whereas proline transport of the vesicles was insensitive to antibody. These results suggest that most of the membrane vesicles have D-lactate dehydrogenase on the inside of the membrane and that such vesicles transport amino acids. This essentially confirms the results of Short, Kaback, and Kohn (1975). However, unlike them we observed that a small but significant portion of activity was sensitive to the antibody as shown above. This portion may represent the completely inverted vesicles in the preparation. Ferricyanide reductase activity cannot be detected in spheroplasts, but about 30 to 50% of the total was detected in membrane vesicles prepared by treatment with ethylenediaminetetraacetate. This confirms our previous findings with membrane prepared by a slightly different procedure. It is concluded that in these vesicles about half the reactive sites for ferricyanide are moved from inside to outside the membrane, whereas 85% of the D-lactate dehydrogenase remains inside the membrane.
...
PMID:Localization of D-lactate dehydrogenase in membrane vesicles prepared by using a french press or ethylenediaminetetraacetate-lysozyme from Escherichia coli. 80 22

In 22 biological tests a study was made of the properties of 1117 strains of staphylococci isolated from patients and medical personnel surgical departments. The significance of each of the tests for species identification of staphylococci was assessed on the basis of correlation of its results with the results of study of 3 main signs characteristic of S. aureus: the presence of coagulase, anaerobic mannite fermentation, and of DNA-ase. Besides the ones pointed out the following could be considered as properties characteristic of S. aureus: flocculus-forming factor, fibrinolysin, hyaluronidase, lysozyme, golden pigment, tellurite-reductase, aerobic fermentation of mannite and tregalose. A standard system of species identification of staphylococci was elaborated; on its basis assessment was made of the diagnostic value of a number of simple systems used in practice for determination of staphylococcus species.
...
PMID:[Indentification of staphylococci of hospital origin. I. Specific identification of staphylococci]. 96 Dec 42

Subcellular distribution study of cytoplasmic organelles was performed on human polymorphonuclear leukocytes after homogenization in 0.34 molar sucrose by differential centrifugation and sucrose density gradient centrifugation of the homogenate. The whole homogenate and each fraction was assayed for nitroblue tetrazolium (NBT)-reductase with and without 1 mM potassium cyanide, and the distribution of this enzyme was compared to the distribution of lysozyme, peroxidase, beta-glucuronidase, and acid and alkaline phosphatase. Enzyme recovery was 97 per cent and ranged between 74 and 124 per cent. Latent activity of all enzymes except NBT-reductase, acid, and alkaline phosphatase was demonstrated by observing a four- to sixfold increase in activity after the addition of Triton-X 100. Maximal relative specific activity using either DPNH or without cyanide for NBT-reductase was found in the 100,000 x g differential centrifugation fraction and was concentrated in the less dense top fraction of the sucrose density gradient. The distribution pattern was similar to acid and alkaline phosphatase. In contrast, the maximal concentration of beta-glucuronidase and peroxidase was found in the heavier 7,200 x g granule fraction and in the more dense bottom fractions of the sucrose density gradient. Maximal lysozyme activity was concentrated in the 30,000 x g granule fraction and in the fractions located between the heaviest and lightest fractions of the sucrose density gradient. The lack of latent activity and the similarity of subcellular distribution of NBT-reductase to acid and alkaline phosphatase, two enzymes associated with microsomes and plasmalemal membranes in human polymorphonuclear leukocytes (PMN), indicates that NBT-reductase is also a nonlysosomal enzyme located in microsomes or in plasmalemal membranes. These findings support the previously described histochemical observations that initial reduction of NBT to formazan occurs on the PMN plasmalemal surface membrane at the point of particle attachment. In addition, they suggest that alteration of the surface membrane of the PMN by particle attachment or other surface forces may activate NBT-reductase, leading to an accumulation of formazan in the region of the altered membrane as the phagocytic vacuole is formed.
...
PMID:Subcellular distribution of nitroblue tetrazolium reductase (NBT-R) in human polymorphonuclear leukocytes (PMN). 118 38

The human promyelocytic cell line HL-60, differentiates in response to a variety of agents including dibutyryl cAMP and agents which increase intracellular cAMP concentrations (phosphodiesterase inhibitors, PGE2, and cholera toxin). HL-60 is also known to be rich in H2 -histamine sensitive adenylate cyclase activity. The present study was therefore designed to test the effects of H2-stimulation on growth and differentiation of HL-60 using the potent H2 agonist dimaprit. Dimaprit markedly increased cAMP production in a dose-dependent manner reaching maximal levels after 30-60 minutes. Intracellular cAMP levels decreased thereafter and by 24 hours were approximately 2-3 fold increased above control. Intracellular cAMP levels were not altered by dimaprit (10(-7)M to 10(-4)M) at 4 days in culture compared to either untreated HL-60 cells or dimethylsulfoxide (DMSO) (1.3%) treated cells. While exponential growth was unaltered by dimaprit (10(-7)M to 10(-4)M) as compared to control, dimaprit induced i) morphologic maturation to the myelocyte and metamyelocyte form with no differentiation seen beyond the metamyelocyte even after 6 days in culture, ii) increased NBT reductase activity and iii) dose-dependent increase in lysozyme activity which could be completely blocked by cimetidine, a specific H2 antagonist. Dimaprit-induced differentiation of HL-60 cells was associated with an initial but transient increase in intracellular cAMP production. Maturation beyond the metamyelocyte stage was not observed. Acquisition of NBT reductase and lysozyme activity correlated with morphologic maturation.
...
PMID:Effects of dimaprit on growth and differentiation of human promyelocytic cell line, HL-60. 298 4

The activity of beta-D-glucuronidase (BDG) was lowered and the activity of myeloperoxidase (MPO) was elevated in polymorphonuclear leukocytes (PMNs) of SLE patients compared with normal subjects. After levamisole treatment, the activities of BDG, MPO, and lysozyme rose in PMNs of SLE patients. A higher activity of lysozyme was also observed in peritoneal PMNs of rabbits after levamisole administration. During incubation of human phagocytizing and non-phagocytizing PMNs, no effects of levamisole at concentrations of 10(-3) to 10(-5) M were observed on the release of lysosomal enzymes. These concentrations of levamisole also did not influence INT reductase activity and production of superoxide by normal human PMNs in the presence of zymosan particles. These findings suggest that levamisole might have an effect on the actual level of lysosomal enzymes in PMNs rather than on their release.
...
PMID:Lysosomal enzymes and metabolic activity of polymorphonuclear leukocytes from patients with systemic lupus erythematosus and from experimental animals after levamisole treatment. 629 8

1. A method is described for preparing spheroplasts from Paracoccus denitrificans that are substantially depleted of dissimilatory nitrate reductase (cytochrome cd) activity. Treatment of cells with lysozyme + EDTA together with a mild osmotic shock, followed by centrifugation, yielded a pellet of spheroplasts and a supernatant that contained d-type cytochrome. The spheroplasts were judged to have retained an intact plasma membrane on the basis that less than 1% of the activity of a cytoplasmic marker protein, malate dehydrogenase, was released from the spheroplasts. In addition to a low activity towards added nitrite, the suspension of spheroplasts accumulated the nitrite that was produced by respiratory chain-linked reduction of nitrate. It is concluded that nitrate reduction occurs at the periplasmic side of the plasma membrane irrespective of whether nitrite is generated by nitrate reduction or is added exogenously. 2. Further evidence for the integrity of the spheroplasts was that nitrate reduction was inhibited by O2, and that chlorate was reduced at a markedly lower rate than nitrate. These data are taken as evidence for an intact plasma membrane because it was shown that cells acquire the capability to reduce nitrate under aerobic conditions after addition of low amounts of Triton X-100 which, with the same titre, also overcame the permeability barrier to chlorate reduction by intact cells. The close relationship between the appearance of chlorate reduction and the loss of the inhibitory effect of O2 on nitrate reduction also suggests that the later feature of nitrate respiration is due to a control on the accessibility of nitrate to its reductase rather than on the flow of electrons to nitrate reductase.
...
PMID:The location of dissimilatory nitrite reductase and the control of dissimilatory nitrate reductase by oxygen in Paracoccus denitrificans. 719 18

Biliverdin reductase in a stable form was purified to homogeneity from rat liver cytosol. The purified enzyme showed 3700-fold increase in specific activity when compared with the crude preparation, and the extent of recovery was 30-35%. The molecular weight was estimated at 34,000-36,000. The amino acid analysis of the purified preparation revealed the presence of 3 cysteine residues/mol of enzyme. The reductase utilized NADPH and NADH as electron donors. The NADPH-dependent biliverdin reductase activity was extremely sensitive to SH reagents, including 5,5'-dithiobis(2-nitrobenzoic acid), N-ethylmaleimide, p-chloromercuribenzoic acid, and iodoacetamide. However, the pretreatment of the enzyme with NADPH and biliverdin fully protected the reductase from inactivation by these reagents. The enzyme activity was irreversibly inhibited by HgCl2. The addition of dithiothreitol to the enzyme inhibited by 5,5'-dithiobis(2-nitrobenzoic acid) promoted the full reversal of inhibition. The enzyme exhibited different pH optima for activity with NADPH (pH 8.7) and NADH (pH 7.0). The apparent Km for biliverdin was established to be 5.0 microM with NADH and 3.0 microM with NADPH. The apparent Km for NADPH was 3.0 microM, while that of NADH was 270 microM. The enzyme activity was inhibited by the substrate when the concentration exceeded 4.0-5.0 microM. The product, bilirubin, inhibited the enzyme activity in a competitive manner. In addition, the reductase was inhibited by hematin and zinc-protoporphyrin. Dilution produced instability in the enzyme, but the presence of exogenous proteins, such as serum albumin, beta-lactoglobulin, and lysozyme, stabilized the enzyme protein.
...
PMID:Purification and characterization of biliverdin reductase from rat liver. 721 67

Various dehydrogenases, reductases, and electron transfer proteins involved in respiratory sulfate reduction by Desulfovibrio gigas have been localized with respect to the periplasmic space, membrane, and cytoplasm. This species was grown on a lactate-sulfate medium, and the distribution of enzyme activities and concentrations of electron transfer components were determined in intact cells, cell fractions prepared with a French press, and lysozyme spheroplasts. A significant fraction of formate dehydrogenase was demonstrated to be localized in the periplasmic space in addition to hydrogenase and some c-type cytochrome. Cytochrome b, menaquinone, fumarate reductase, and nitrite reductase were largely localized on the cytoplasmic membrane. Fumarate reductase was situated on the inner aspect on the membrane, and the nitrite reductase appeared to be transmembraneous. Adenylylsulfate reductase, bisulfite reductase (desulfoviridin), pyruvate dehydrogenase, and succinate dehydrogenase activities were localized in the cytoplasm. Significant amounts of hydrogenase and c-type cytochromes were also detected in the cytoplasm. Growth of D. gigas on a formate-sulfate medium containing acetate resulted in a 10-fold increase in membrane-bound formate dehydrogenase and a doubling of c-type cytochromes. Growth on fumarate with formate resulted in an additional increase in b-type cytochrome compared with lactate-sulfate-grown cells.
...
PMID:Localization of dehydrogenases, reductases, and electron transfer components in the sulfate-reducing bacterium Desulfovibrio gigas. 724 92

Genetic variation of the glucocorticoid receptor (GR) locus is associated with differences in blood pressure. To define the intermediate phenotypes associated with this variation, we investigated the biochemical and clinical significance of a BclI restriction fragment length polymorphism of the GR locus in 64 normal male volunteers. Blood samples were genotyped as either AA (homozygous large allele; n = 6), Aa (heterozygous; n = 51), or aa (homozygous small allele, n = 7). Four primary glucocorticoid variables were measured including GR binding characteristics and glucocorticoid-sensitive lysozyme release of leukocytes in vitro and the blanching response of forearm skin to budesonide. A large number of secondary variables (urinary and plasma steroid measurements, blood pressure and indices of body fat metabolism, and routine biochemical and hematological measurements) were also considered. In vivo sensitivity to budesonide was greater in AA than aa individuals (mean +/- SE EC50 values: 13 +/- 5 and 42 +/- 10 ng; P < 0.01). In contrast, leukocytes of AA subjects tended to have lower affinity and reduced sensitivity for dexamethasone, although these effects were not statistically significant. Based on urinary steroid measurements, 11 beta-hydroxysteroid dehydrogenase activity [ratio of tetrahydrocortisol (THF) to tetrahydrocortisone (THE) metabolites] was not affected by genotype. The relative activities of 5 alpha- and 5 beta-reductase activity (allo-THF/THF + THE) appeared lower in AA than aa subjects (0.22 +/- 0.04 cf. 0.33 +/- 0.06; P < 0.005) but were not judged to be significantly different when corrected for multiple comparisons. Single and multivariate analyses were carried out to determine which variables influence GR binding characteristics and glucocorticoid responsiveness and to see whether cardiovascular risk factors (blood pressure and body fat) were influenced by glucocorticoid-dependent functions. Only 15-20% of the variations in the dissociation constant (Kd) and maximum binding capacity (Bmax) were influenced by other variables; plasma cholesterol was the most important for affinity and plasma sodium concentration for binding capacity. Multivariate analysis showed that several factors including GR genotype and urinary cortisol account for 10% of the variation of in vivo responses to glucocorticoid hormones; plasma calcium concentration was the only variable that contributed to in vitro sensitivity of leukocytes to dexamethasone. Glucocorticoid-dependent responses were of negligible importance in determining blood pressure or percentage body fat within the narrow physiological ranges of the present study. We conclude that GR genotype affects steroid sensitivity in a tissue-specific manner because of altered GR function or possibly because of linkage to a locus that controls hormone access to the receptor by influencing steroid metabolism.
...
PMID:Glucocorticoid receptor polymorphism, skin vasoconstriction, and other metabolic intermediate phenotypes in normal human subjects. 962 6

DsbC, a periplasmic disulfide isomerase of Gram-negative bacteria, displays about 30% of the activities of eukaryotic protein disulfide isomerase (PDI) as isomerase and as thiol-protein oxidoreductase. However, DsbC shows more pronounced chaperone activity than does PDI in promoting the in vitro reactivation and suppressing aggregation of denatured D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) during refolding. Carboxymethylation of DsbC at Cys98 decreases its intrinsic fluorescence, deprives of its enzyme activities, but lowers only partly its chaperone activity in assisting GAPDH reactivation. Simultaneous presence of DsbC and PDI in the refolding buffer shows an additive effect on the reactivation of GAPDH. The assisted reactivation of GAPDH and the protein disulfide oxidoreductase activity of DsbC can both be inhibited by scrambled and S-carboxymethylated RNases, but not by shorter peptides, including synthetic 10- and 14-mer peptides and S-carboxymethylated insulin A chain. In contrast, all the three peptides and the two nonnative RNases inhibit PDI-assisted GAPDH reactivation and the reductase activity of PDI. DsbC assists refolding of denatured and reduced lysozyme to a higher level than does PDI in phosphate buffer and does not show anti-chaperone activity in HEPES buffer. Like PDI, DsbC is also a disulfide isomerase with chaperone activity but may recognize different folding intermediates as does PDI.
...
PMID:Chaperone activity of DsbC. 1039 95


1 2 Next >>

---