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)

To determine whether tubular reabsorption of low molecular weight proteins (LMWPs) alters ischemic tubular injury, rats were infused with 25 mg of lysozyme (isoelectric point (pI) 11.3), cytochrome C (pI 10.6), ribonuclease (pI 8.7), or myoglobin (pI 7.0), and during this time 25 minutes of bilateral renal artery occlusion (RAO) was induced. RAO control rats received either saline or 25 mg of albumin. Renal injury was assessed 24 hours later by blood urea nitrogen, creatinine, and histology. Lysozyme, ribonuclease, and myoglobin each exacerbated ischemic damage (increased tubular necrosis, cast formation, azotemia), but to comparable degrees (e.g., blood urea nitrogen range 75 +/- 8 to 100 +/- 5 mg/dl versus controls, 29 +/- 2 to 36 +/- 7; p less than 0.01). Rendering lysozyme anionic (pI 4.5) by succinylation did not diminish its acute renal failure-potentiating effect. Cytochrome C which is freely filtered but poorly reabsorbed had a minimal impact on the ischemic process. Infusion of LMWPs did not alter blood pressure, renal blood flow, or induce renal injury in the absence of RAO. During a sublethal ischemic event (10 minutes of RAO) LMWP infusion exacerbated proximal tubular luminal membrane damage before an adverse effect on other critical determinants of cell integrity were apparent (adenine nucleotide pools, oxidant stress). We conclude that endocytic LMWP reabsorption by proximal tubules can exacerbate superimposed ischemic tubular necrosis independent of any direct nephrotoxic protein effect. This action is not influenced by protein isoelectric point and appears to be mediated by a primary intensification of ischemic luminal membrane damage.
...
PMID:Low molecular weight proteinuria exacerbates experimental ischemic renal injury. 380 17

A method has been developed for measuring the adhesion of platelets to purified collagen fibers obtained from bovine tendon. This method differs from others in that: (a) platelet adhesion is measured in the absence of platelet aggregation; (b) platelet-rich plasma collected in ACD (acid citrate dextrose) or EDTA, or washed platelets can be employed; (c) adherent platelets are enumerated directly; (d) erythrocytes and leukocytes do not adhere. Washed platelets suspended in human Ringer solution exhibit negligible adhesion (at the platelet concentrations employed) in contrast to washed platelets suspended in plasma. Addition of purified human fibrinogen (95% clottable, 2-4 mg/ml) to human Ringer solution completely restores the ability of washed platelets to adhere to collagen fibers. Albumin (fatty acid free, 50 mg/ml) is also capable of restoring adhesion. Albumin and seven other proteins at concentrations of 5-10 mg/ml, with varying molecular weights, isoelectric points, and frictional coefficients are incapable of supporting the adhesion of washed platelets. The proteins tested were human globulin, hexokinase, hemoglobin, cytochrome-C, insulin, thyroglobulin, and muramidase. Platelet adhesion is proportional to both platelet concentration and fibrinogen concentration, but is independent of temperature or glycogen stores. Modification of fibrinogen by acylation of amino groups or removal of sialic acid has no effect on its ability to support platelet adhesion. Degradation of fibrinogen with purified plasmin results in decreased support of platelet adhesion. This accompanied formation of early breakdown products with clottability ranging from 84-0%. Formation of fibrinogen degradation products was monitored by SDS-polyacrylamide gel electrophoresis of the corresponding fibrins after reduction of disulfide bonds (a method capable of distinguishing alpha-, beta- and gamma-chains). Decreased support of platelet adhesion is associated with the disappearance of intact alpha- chains and early modification of the beta-chains. Purified proteinpolysaccharide macromolecules obtained from bovine nasal and humeral cartilage, and from nucleosus pulposus are as effective as fibrinogen on a weight basis and ten to thirty times more effective on a molar basis in supporting platelet adhesion. The purified mucopolysaccharide side chains: chondroitin-4-sulfate, chondroitin-6-sulfate, and keratan-sulfate are incapable of supporting platelet adhesion.
...
PMID:Biochemical and biophysical aspects of human platelet adhesion to collagen fibers. 556 92

A method for studying inhibitors of the contact stages of blood coagulation is described. A number of positively charged substances were shown to inhibit the contact stages. The inhibitory substances include spermine, cytochrome c, ribonuclease, and lysozyme. The inhibitory effect of these substances was neutralized by the addition of an activated plasma thromboplastin antecedent, factor XI, (PTA) fraction. Other positively charged substances including protamine, hexadimethrine, polylysine, polyornithine, methylene blue, and ortho-toluidine blue also inhibited the contact stages of coagulation, but the inhibitory effect on coagulation was not neutralized by the activated PTA fraction. Negatively charged substances such as heparin and insulin did not inhibit the contact stages of coagulation. Cytochrome c inhibited Celite adsorption of a partially purified Hageman factor fraction, and cytochrome, ribonuclease, spermine, and lysozome inhibited the adsorption of Hageman factor from PTA-deficient plasma. Very much smaller quantities of Celite completely adsorbed Hageman factor from the fraction rather than from whole plasma, which suggested the possibility that plasma contains an inhibitor or inhibitors of Hageman factor adsorption. Furthermore cytochrome c, spermine, ribonuclease, and lysozyme inhibited the coagulant activity of the following activators of the Hageman and PTA factors: Celite, kaolin, sodium stearate, ellagic acid, and skin. It is suggested that negatively charged sites on these activators are critical for adsorption and activation and that inhibition results from neutralization of the negatively charged sites by the adsorbed inhibtor. Tests with polylysine polymers indicate that inhibitory activity is directly related to molecular size over the molecular weight range of 4000 to 100,000.
...
PMID:Inhibition of Hageman factor activation. 564 60

Human colostral macrophages stimulated by opsonized zymosan or phorbol myristate acetate (PMA) released superoxide anions (O2-) and hydrogen peroxide (H2O2) with activities comparable to those of monocytes and about one-fourth of those of polymorphonuclear leukocytes (PMNL) of blood. The O2- -forming oxidase in the macrophages stimulated by PMA was dependent on NADPH as an electron donor with an apparent Km value for NADPH of 27.6 +/- 4.0 microM, which is comparable to those obtained for the stimulated monocytes and PMNL of blood. The Vmax was 1.86 +/- 0.33 nmol O2/min/10(6) cells, which is essentially the same as that of monocytes and about half of that of PMNL. p-Chloromercuribenzoate or cetyltrimethylammonium bromide completely inhibited oxidases of all three types of phagocytes. A b-type cytochrome was identified in the macrophages but the concentrations in the macrophages and monocytes were less than half of that in PMNL. These results suggest that the differences in the O2- -forming activities of the three types of phagocytes are quantitative rather than qualitative. The macrophages and monocytes showed very low activities of myeloperoxidase [EC 1.11.1.7] in contrast to PMNL. The activity of beta-glucuronidase [EC 3.2.1.31] in the macrophages was much higher than those of the monocytes and PMNL, but little difference was observed in the activities of lysozyme [EC 3.2.1.17], catalase [EC 1.11.1.6] and superoxide dismutase [EC 1.15.1.1] among the three types of phagocytes examined. Electron micrographs of the macrophages showed little increase of vacuoles upon exposure to PMA, in contrast to the cases of monocytes and PMNL.
...
PMID:Oxygen metabolism of human colostral macrophages: comparison with monocytes and polymorphonuclear leukocytes. 608

Lysozyme, cytochrome c, poly(L-lysine), myelin basic protein and ribonuclease were used to form multilayer dispersions containing about 50% protein (by weight) with bovine brain diacyl phosphatidylserine (PS). 31P nuclear magnetic resonance shift anisotropies, spin-spin (T2) and spin-lattice (T1) relaxation times for the lipid headgroup phosphorus were measured at 36.44 MHz. At pH 7.5, lysozyme, cytochrome c, poly(L-lysine) and ribonuclease were shown to increase the chemical shift anisotropy of PS by between 12-20%. Myelin basic protein altered the shape of the phosphate resonance, suggesting the presence of two lipid components, one of which had a modified headgroup conformation. The presence of cytochrome c led to the formation of a narrow spike at the isotropic shift position of the spectrum. Of the various proteins or peptides we have studied, only poly(L-lysine) and cytochrome c had any effect on the T1 of PS (1050 ms). Both caused a 20-30% decrease in T1 of the lamellar-phase phosphate peak. The narrow peak in the presence of cytochrome c had a very short T1 of 156 ms. The possibility is considered that the cytochrome Fe3+ contributes to the phosphate relaxation in this case. The effect of all proteins on the T2 of the phosphorus resonance was to cause an increase from the value for pure PS (1.6 ms) to between 2 and 5 ms. The results obtained with proteins are compared with the effects of small ions and intrinsic membrane proteins on the order and motion of the headgroups of lipids in bilayers.
...
PMID:31P nuclear magnetic resonance studies of the association of basic proteins with multilayers of diacyl phosphatidylserine. 619 74

Conformation wheels, directly relating to amino acid sequence to the local torsion angles in a protein molecule, are presented for cytochromes c, c2, c550, and c551 and for lysozymes from hen egg-white and T4 bacteriophage. The circular plots for the cytochrome molecules aid in visualizing the common three-dimensional folding ("cytochrome fold") observed in this family of proteins. Conformation wheels for lysozymes from two different species reveal the characteristic differences in their folding patterns. These novel plots are also useful in storing and comparing the several sets of crystallographic data reported for lysozyme.
...
PMID:Protein conformation wheels: cytochromes and lysozymes. 625 19

The adsorption of lysozyme on mixed phosphatidyl choline-cardiolipin vesicles was studied at pH 4.0 and 6.0. The binding constants at both pH were determined at 0 and 22 degrees C. The presence of maximum on the adsorption isotherm at pH 6.0 was interpreted as an indication of the formation of two types of the protein-lipid complexes. This interpretation was confirmed by electron-microscopic observations. On the other hand, at pH 4.0 only one type of the protein-lipid complex was formed. The lysozyme conformation in solution and in the protein-lipid complexes was studied by circular dichroism. It was found that at acidic pH the lysozyme molecule contains a higher per cent of alpha-helix segments than at neutral pH. As follows from the measurements of lysozyme distribution in two phase systems the increase in alpha-helicity results in the formation of hydrophobic patches on the surface of the protein molecule. The results of the present work and of the previous studies of the interaction of red- and oxy- form of cytochrome C with phospholipid allow the conclusion that for peripheral proteins the nature of protein-lipid interactions is determined by the protein alpha-helix content and by hydrophobic pattern of the protein molecule surface.
...
PMID:[Influence of protein molecule conformation on the character of its interaction with a phospholipid bilayer]. 630 96

Polypeptide and polysaccharide outer membrane components of Brucella abortus 99 (S) were investigated by analysis of cell-wall fractions by sodium dodecyl-sulfate polyacrylamide gel electrophoresis and staining with coomassie blue and periodic acid silver stain. Crude cell-walls were deprived by Triton X-100 treatment of most cytoplasmic material as seen by electron microscopy and cytochrome determination (cell-walls). They were submitted to hot SDS to obtain intentionally after centrifugation, peptidoglycan in the insoluble fraction: SDS-I fractions or peptidoglycan sacculi, and outer membrane components in the SDS soluble fraction as for Enterobacteriaceae. The SDS-soluble fraction contained two major components: a high molecular weight broad band of smooth lipopolysaccharide (S-LPS) and a 43k polypeptide band. The SDS-I fractions were treated by lysozyme to solubilize peptidoglycan before analysis. They contained two major polypeptide groups 36-37-38k, 25-26-27k, a minor one at 31k and variable amounts of high molecular weight S-LPS. The polypeptide and polysaccharide patterns of the entire outer membrane obtained from lysozyme hydrolysed cell-walls are the sum of both SDS soluble and insoluble fraction patterns. These results mean that 25-27k and 36-38k bands are strongly bound to peptidoglycan, probably covalently. The 25-26-27k bands heavily stained for polysaccharides would be glycopolypeptides. In addition, the polysaccharide patterns of S-LPS fraction appears as a high molecular weight broad band, contrary to the multiple regularly spaced bands of high molecular weight E. coli S-LPS. The B. abortus outer membrane is composed of four major components: LPS, 43k and 36-37-38k polypeptides and 25-26-27k glycopeptides.
...
PMID:Evidence of three major polypeptide species and two major polysaccharide species in the Brucella outer membrane. 641 68

Heterocysts of the blue-green alga Nostoc muscorum have been isolated by prolonged treatment with lysozyme. Quantitative data are presented which show the occurrence of cytochromes c-553, f-557 and b-563 in heterocysts in amounts comparable to vegetative cells. Particularly the content of the water-soluble cytochrome c-553 can be used to evaluate the intactness of a heterocyst preparation. Cytochrome f-557 has been partially purified and found to be a c-type cytochrome corresponding to cytochrome f of higher plants and other algae. Cytochrome b-559 is present in vegetative cells but not in heterocysts. The content of plastoquinone in heterocysts is reduced to 42% of the amount present in vegetative cells. These data suggest a degradation of Photosystem II during heterocyst differentiation. Measurements of photosynthetic electron transport in heterocysts proved the inability of the photosynthetic apparatus to carry out electron transport with electrons donated by water or diphenylcarbazide. In Tris-washed thylakoids from vegetative cells, however, diphenylcarbazide can act as an electron donor to Photosystem II.
...
PMID:Components and activity of the photosynthetic electron transport system of intact heterocysts isolated from the blue-green alga Nostoc muscorum. 677 15

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


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

---