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)

Incubation of crude estrogen receptor preparations from mammary tumor cytosol with RNase A increases the sedimentation coefficient of the receptor from 9.7 S to 10.4 S. The effect is not obtained with other low molecular weight basic proteins (lysozyme, cytochrome c, or histone H2B). Nonenzymically active RNase A derivatives such as performic acid oxidized RNase A, fully reductively methylated RNase A, carboxymethyl-His-119-RNase A, and RNase S-protein were ineffective. RNase T1, an acidic endoribonuclease, was also without effect. However, enzymically active RNase S', prepared from a mixture of RNase S-protein and S-peptide, shifted the sedimentation to 10.4 S. The increased sedimentation is not accompanied by a change in the Stokes radius of the receptor (74 A) or buoyant density in metrizamide (1.24 g/ml). The effect of RNase A on the sedimentation of the receptor can be reversed by subsequent incubation with human placental RNase inhibitor or with rabbit anti-RNase A antibodies. Direct interaction was shown by chromatography of the receptor on RNase A Sepharose. Thus, the shift in sedimentation results from binding of RNase A to the receptor and, although this requires that the enzyme active site be available, enzymic activity is not responsible for the effect. The interaction of RNase A with the receptor occurs at low ionic strength; it does not occur at elevated ionic strength or after activation of the receptor by precipitation with ammonium sulfate.
...
PMID:Interaction of ribonuclease A with estrogen receptor from rat mammary tumor MTW9. 683 88

Polymorphonuclear leucocytes were isolated from pig blood relatively free from other cells and were characterised biochemically and morphologically and compared with human PMNLs. The activities of 16 enzymes of porcine and human PMNLs were measured and compared. Alkaline phosphatase, acid phosphatase, phosphodiesterase, gamma-glutamyl transpeptidase, NADH-cytochrome c oxidoreductase, malate dehydrogenase and acetylcholinesterase had higher specific activities in procine than in human cells. Alkaline phosphatase has an 87-fold higher specific activity in porcine than in human cells. beta-glucuronidase, lysozyme, beta-galactosidase, N-acetyl-glucosaminidase, beta-glucosidase, myeloperoxidase and catalase had higher specific activities in human than in porcine cells. beta-glucuronidase and myeloperoxidase showed over a 1000- and a 13-fold higher specific activity, respectively, in human than in porcine cells. Porcine PMNLs are readily available in large numbers and are recommended for studies of phagocytosis, chemotaxis and membrane biochemistry.
...
PMID:Biochemical characterisation of porcine polymorphonuclear leucocytes: comparison with human polymorphonuclear leucocytes. 687 22

A simple dipole model is developed for estimation of the electrostatic interaction energy between alpha-helices in proteins. This model is used to estimate the electrostatic stabilization in a recurrent protein tertiary structural motif, an array of four closely packed alpha-helices. It is found that, for the proteins examined (cytochrome c', hemerythrin, myohemerythrin, cytochrome b562, and a T4 phage lysozyme domain), their common antiparallel arrangement of adjacent helices confers a stabilization of 5--7 kcal/mol (1 cal = 4.18 J). In contrast, a similarly packed array of parallel helices is relatively destabilized by 20 kcal/mol. These results show that helix-dipole interactions are important in the stabilization of this structural motif. These effects are discussed both in the context of folding pathways for 4-alpha-helical proteins and the stabilization of the higher aggregates.
...
PMID:alpha-Helix dipole model and electrostatic stabilization of 4-alpha-helical proteins. 695 78

Tubular absorption (T) of two cationic proteins, lysozyme (LZM) and cytochrome c (CYT c), and two anionic proteins, beta 2-microglobulin (beta 2M) and 125I-labeled human growth hormone (hGH), was studied in the isolated perfused rat kidney. All four proteins are extensively filtered and, at low loads, almost completely absorbed by the tubular epithelium. TLZM and TCYT c is a saturable process of high capacity (Tm) and low apparent affinity. (Tm)LZM was two orders of magnitude larger than (Tm)CYT c. LZM inhibited TCYT c in a dose-dependent and reversible manner. Saturating loads of CYT c failed to inhibit T beta 2M and ThGH. Saturation, selectivity, and competition is explained on the basis of a model that incorporates adsorption of protein to microvilli as well as geometric and electrical constraints on the access of filtered proteins to endocytic sites at the base of the microvilli. Tubular absorption of all proteins is decreased by inhibitors of the formation and/or internalization of endocytic vesicles (iodoacetate and cytochalasin B). However, lysine (5 mM) and low perfusate calcium concentration (0.5 mM) inhibited T beta 2M but not TCYT c and ThGH. The selective effect of 5 mM lysine, which causes morphologic damage in initial portions of the proximal convoluted tubule, may be due to preferential or exclusive absorption of beta 2 M in this portion of the nephron. The results as a whole demonstrate that in addition to net charge other structural features of the protein molecule and of the luminal wall of proximal tubules may be important determinants of the efficiency and capacity of the tubular absorption of filtered proteins.
...
PMID:Kinetics, competition, and selectivity of tubular absorption of proteins. 712 51

Pyocyanin being added to protein solutions influenced the intensity of the subsequent chemiluminescence caused by KMnO4. The amplitude of chemiluminescence for albumin, peptone and peroxidase decreased by 38, 39 and 42%, respectively. Pyocyanin had only a minor effect on the chemiluminescence of alcohol dehydrogenase; it decreased the intensity of the reaction by 7%. The reaction of chemiluminescence for cytochrome c and lysozyme did not change in the presence of pyocyanin.
...
PMID:[Effect of pyocyanin on the intensity of KMnO4-induced protein chemiluminescence]. 744 75

Immunoglobulin light chains, beta 2-microglobulin, insulin, and lysozyme are low-molecular-weight proteins (LMWP) shown to bind to renal brush border membranes. Competition among these proteins and the role of electrical charge in binding to brush border membranes have not been resolved. To investigate these factors, we performed displacement experiments with [125I]-labeled beta 2-microglobulin (pI = 5.6) using six species of LMWP over a pI range of 4.4-11.0. The inhibition constants, Ki, of these six competing ligands, kappa- and lambda-light chains, lysozyme, insulin, cytochrome c, and myoglobin, determined from the log displacement curves, ranged from 4 x 10(-5) to 8 x 10(-4) M. These experiments show marked cross-competition among LMWP for binding to brush border membranes. There was no correlation between Ki and pI indicating that the molecular structure is a more important determinant of LMWP binding to brush border membranes than net electrical charge.
...
PMID:Low-molecular-weight protein competition for binding sites on renal brush border membranes. 753 7

Effects of 10-30% (v/v) of dimethyl sulfoxide, glycerol, and ethylene glycol on the H-O-H bending vibration of water and the amide I bands of horse heart cytochrome c and chicken egg white lysozyme in 25 mM sodium phosphate buffer (pH 7.4) were examined at 20 degrees C by Fourier transform infrared spectroscopy. The H-O-H bending mode of water was strongly affected by these cryoprotectant solvents. Increasing the concentration of cryosolvents from 0 to 30% shifts the water bending band maximum from 1645 to about 1650 cm-1. Second-derivative analysis reveals significant changes in conformation-sensitive amide I regions of lysozyme ascribed to alpha-helix (1657 cm-1), turn (1674 cm-1), and unordered (1646 cm-1) structures; each cryosolvent increases the intensity of the 1657 cm-1 band at the expense of bands at 1674 and 1646 cm-1. No changes in spectra deemed significant were observed for cytochrome c under the same conditions. There is no spectral evidence of structural randomization of proteins due to the presence of these cryosolvents. Cryosolvent-induced changes in secondary structure of proteins may result from changes in water structure which, in turn, perturb the structure of the protein and/or from direct interactions between cryosolvent and protein.
...
PMID:Effects of dimethyl sulfoxide, glycerol, and ethylene glycol on secondary structures of cytochrome c and lysozyme as observed by infrared spectroscopy. 762 25

delta 9-Tetrahydrocannabinol (THC) exposure suppresses multiple immunological functions of macrophages. The ability of macrophages exposed to THC to process and present soluble protein antigens was investigated by the stimulation of antigen-specific helper T cell hybridomas to secrete interleukin-2. The T cell response to hen egg lysozyme was dramatically reduced after a 24-hr pretreatment of a macrophage hybridoma with THC. In contrast, THC exposure did not alter the capacity of the macrophage hybridoma to process chicken ovalbumin and augmented their presenting cell function for a pigeon cytochrome c response. These findings could not be attributed to differential effects of THC on either cell viability or expression of the antigen receptor-associated CD3 complex by the T cells. The level of T cell activation with peptides of lysozyme and cytochrome c, which do not require processing, was inhibited only at the highest concentrations of THC, suggesting that THC mainly affects antigen processing. Peritoneal macrophages exposed to THC during an antigen pulse and fixed with paraformaldehyde showed similar effects on the subsequent T cell responses to lysozyme and cytochrome c in the absence of THC, arguing against a possible influence of THC on the T cells. Therefore, THC differentially modulates the capacity of macrophages to process antigens that is necessary for the activation of CD4+ T cells.
...
PMID:delta 9-Tetrahydrocannabinol modulates antigen processing by macrophages. 779 Oct 94

We report here a comprehensive infrared spectroscopic study of the interactions between the anesthetic nitrous oxide (N2O) and six proteins: lysozyme, cytochrome c, myoglobin, hemoglobin, serum albumin, and cytochrome c oxidase. Sites occupied by N2O molecules within these proteins were characterized. Three types of hydrophobic sites were found within the proteins. One with nu 3 near 2225 cm-1 is likely to be near peptide bond carbonyls; one with nu 3 near 2219 cm-1 may be near a benzene-like structure such as the side chains of phenylalanine and tyrosine; and the other with nu 3 near 2215 cm-1 is likely to be in a nonpolar alkane-like environment provided by the side chains of Leu, Ile, and Val residues. The amount of N2O molecules bound to myoglobin increases as the pH decreases from 9.2 to 5.2. N2O-protein interactions produced no detectable changes in the ligand-binding pockets of myoglobin, hemoglobin, and cytochrome c oxidase. N2O-induced secondary structure changes were detected only in the fully reduced cytochrome c oxidase, not in the fully oxidized oxidase and the other five proteins. N2O-induced conformational changes in the alpha beta-interface of hemoglobin and the h2 and h3 alpha-helices of human serum albumin were detected by monitoring the S-H stretch vibrations of cysteine residues. These findings provide direct evidence that anesthetic N2O interacts with proteins and occupies sites in the interior of the proteins.
...
PMID:Characterization of sites occupied by the anesthetic nitrous oxide within proteins by infrared spectroscopy. 792 38

Cefdinir, a new oral 2-amino-5-thiazolyl cephalosporin, inhibited the luminol-amplified chemiluminescence (LACL) response of human neutrophils stimulated by PMA but not opsonized zymosan, in a concentration-dependent but not time-dependent manner. The LACL response to opsonized zymosan in cytochalasin B-treated neutrophils was, however, inhibited by cefdinir. Various cephalosporins, regardless of the presence of a 2-amino-5-thiazolyl moiety, did not significantly alter the neutrophil LACL response triggered by PMA and zymosan. The LACL response induced by the calcium ionophore A23187 and FMLP was also impaired by cefdinir, and this impairment was increased in cytochalasin B-treated neutrophils. Superoxide anion generation by neutrophils, measured in terms of lucigenin-amplified chemiluminescence and cytochrome c reduction, was not altered. Spontaneous and FMLP-induced neutrophil degranulation, assessed by lysozyme and beta-glucuronidase release, were not modified by cefdinir. Furthermore, cefdinir inhibited LACL generation in cell-free systems consisting of H2O2, NaI, and either horseradish peroxidase or a myeloperoxidase-containing neutrophil extract. Orthodianisidine oxidation in these two acellular systems was inhibited by cefdinir. Cefdinir did not alter neutrophil bacterial killing at concentrations that inhibited myeloperoxidase-containing neutrophil extract-dependent reactions induced by soluble stimuli. Taken together, these data strongly suggest that cefdinir directly inhibits the activity of myeloperoxidase-containing neutrophil extract released into the extracellular medium during neutrophil stimulation by soluble mediators, but has no effect on that released into the phagolysosome during phagocytosis. This unusual property of a member of the beta-lactam family could be of interest in modulating the exaggerated inflammatory process often associated with infectious diseases.
...
PMID:Cefdinir (CI-983), a new oral amino-2-thiazolyl cephalosporin, inhibits human neutrophil myeloperoxidase in the extracellular medium but not the phagolysosome. 813 56


<< Previous 1 2 3 4 5 6 7 8 9 10

---