Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The oxidative response to phagocytosis by chicken polymorphonuclear leucocytes was investigated as compared to guinea pig polymorphonuclear leucocytes. The polymorphs from both species respond to phagocytosis with an increased oxygen consumption, an increased generation of O2 and H2O2, and an increased oxidation of glucose through the hexose monophosphate shunt. The rate of oxygen consumption, and generation of O2- and H2O2 by phagocytosing chicken polymorphonuclear leucocytes is considerably lower than with phagocytosing guinea pig polymorphonuclear leucocytes. By contrast, the extent of hexose monophosphate shunt stimulation in chicken polymorphs is comparable to that of guinea pig polymorphs. Evidence is presented suggesting that H2O2 is preferentially degraded in chicken cells through the glutathione cycle, whereas catalase and myeloperoxidase are the two main H2O2 degrading enzymes in guinea pig cells. The 20,000 g fraction of the postnuclear supernatant of chicken polymorphs contains a cyanide-insensitive NADPH oxidizing activity which is stimulated during phagocytosis. Similar properties for the NADPH oxidizing activity of guinea pig polymorphs have been previously reported. It is concluded that the metabolic burst of phagocytosing chicken polymorphonuclear leucocytes is qualitatively similar to that of guinea pig polymorphonuclear leucocytes, but the latter cells are more active in all the biochemical parameters that have been measured. The difference in the H2O2 degradation pathways between the two species is accounted for by the lack of myeloperoxidase and catalase in chicken polymorphs.
Mol Cell Biochem 1978 Dec 22
PMID:Oxidative metabolism of chicken polymorphonuclear leucocytes during phagocytosis. 3 93

Hepatic synthesis of apo-B and apo-C and their binding to nascent very low density lipoproteins (VLDL) have been studied in fat-fed rats. Apolipoproteins were located in hepatocyte organelles by light and electron microscopy after immunoenzymatic staining using peroxidase-conjugated antibodies. Our results indicate that apo-B and apo-C are synthesized by membrane-bound ribosomes. Both apoproteins seem to be adsorbed simultaneously to the lipid core of VLDL in the lumen of the endoplasmic reticulum channels, at the junction zone between rough and smooth endoplasmic reticulum. Some additional protein presumably binds nascent VLDL in the Golgi apparatus as judged by the strong positive reaction of lipoprotein particles with peroxidase-labeled antibodies. Finally our data show that significant amounts of apo-B and apo-C are bound to the sinusoidal plasma membrane in fed rat livers which probably represent remnants of lipoprotein of intestinal origin since membrane-bound apolipoproteins virtually disappeared 24 h after lymphatic duct cannulation. It is suggested that nascent VLDL (apo-C poor) could be enriched in apo-C from lipoprotein remnants at the space of Disse.
Virchows Arch B Cell Pathol Incl Mol Pathol 1979 May 31
PMID:Ultrastructural localization of apo-b and apo-c binding to very low density lipoproteins in rat liver. 3 62

The purpose of this study was to determine whether or not endogenous mammary peroxidase can serve as a cytochemical marker to distinguish ovarian hormone-dependent from ovarian hormone independent mammary tumors. Spontaneous mammary tumors arising in virgin C3H and GR mice (hormone independent tumors) and hormone-dependent mammary tumors arising during pregnancy in GR mice were examined. None of these tumors contained mammary peroxidase. Mammary tumors induced in Sprague-Dawley rats with methylnitrousourea (MNU) and dimethylbenzanthracene (DMBA) were also examined. These tumors included hormone-dependent and hormone independent ones. Several of the DMBA-induced hormone-dependent tumors contained a few peroxidase-positive cells, but the hormone independent tumors were negative. All of the MNU-induced tumors examined were negative for mammary peroxidase. Twenty human breast tumors (malignant and non-malignant) removed from women at surgery, were also negative for mammary peroxidase. Our results indicate that endogenous mammary peroxidase cannot be used to distinguish hormone-dependent from hormone independent mammary tumors.
Virchows Arch B Cell Pathol Incl Mol Pathol 1979 Oct
PMID:Analysis of mammary tumors for cytochemical evidence of endogenous mammary peroxidase. 4 10

The oxidation of essential serum proteins, albumin and gamma globulin, by the enzyme peroxidase can be partially inhibited by compounds, such as EDTA and 2,4-pentanedione, that complex with the iron ion in peroxidase. The importance of such inhibition lies in the circumstance that the oxidations in question might be a possible causative factor in tissue aging.
Mol Biol Rep 1977 Jun
PMID:Inhibition of oxidation by peroxidase of human serum proteins. 6 89

The paper presents an experimental procedure for a simultaneous assay of oxygen consumption, O2- release and H2O2 accumulation at a very early stage of the respiratory burst that is induced by phagocytosis in guinea pig polymorphonuclear leucocytes. The main findings are as follows: (a) The oxygen consumption that is measurable does not correspond to all oxygen that is reduced. The relationship between the actual oxygen consumed and the amount that is reduced depends on the fate of the intermediate products O2- and H2O2. (b) O2- is measurable extracellularly by the reduction of cytochrome c. When cytochrome c oxidizes the extracellular O2-, molecular oxygen is formed. This fact is shown by a decrease of oxygen consumption. The molar ratio between the O2- detected and the oxygen given back is 1. (c) The amount of O2- released from the cells accounts for only a small part of oxygen actually reduced. (d) H2O2 is detectable only in the presence of NaN3. In this condition almost all oxygen consumed is recovered in the form of H2O2. The molar ratio O2/H2O2 is near unity. The amount of H2O2 derived from dismutation of O2- released is only an aliquot of the total H2O2 accumulated. Thus, most of H2O2 is derived from intracellular sources. (e) In the absence of inhibitors of H2O2 degrading reactions, no detectable accumulation of peroxide occurs. Under these conditions, the main part of H2O2 formed is degraded in almost equal amount by catalase and myeloperoxidase, while only a small aliquot is degraded by NaN3 insensitive reactions.
Mol Cell Biochem 1979 Jan 26
PMID:Interrelationship between oxygen consumption, superoxide anion and hydrogen peroxide formation in phagocytosing guinea pig polymorphonuclear leucocytes. 22 May 19

Cytochrome P450 in the mitochondria of the adrenal cortex functions in the monooxygenation reactions for the biosynthesis of various steroid hormones, such as cholesterol side chain cleavage, hydroxylation at 11 beta-position and that at 18-position of the steroid structure. The cytochrome is firmly associated with the mitochondrial membrane and therefore can be isolated only by the aid of ionic or non-ionic detergent. Recently, two cytochromes P450 each catalyzing a specified reaction have been purified to a homogeneous state, that is, P450scc having cholesterol side chain cleavage activity and P45011 beta having 11 beta-hydroxylation activity. The properties of these purified P450's as well as the other components of the monooxygenase system, adrenodoxin and adrenodoxin reductase, are, therefore, summarized and compared to those of P450 in the mitochondrial preparation in situ. Among many findings, both purified cytochromes P450 were revealed to be a low-spin type hemoprotein and their spin states were changed to a high-spin state by being complexed with the corresponding substrate. The binding of a substrate also facilitated the reduction of the cytochrome and appeared to increase the stability of the oxygenated form of cytochrome P450. These effects are important from the point of view that the primary role of the heme of cytochrome P450 is the activation of molecular oxygen. In addition, the results of our detailed kinetic studies on the transfer of electrons from adrenodoxin to cytochrome P450 in the reconstituted system have also been described. Finally, the topology of adrenodoxin and the reductase were shown to be on the inner mitochondrial membrane by a peroxidase-labeled antibody method.
Mol Cell Biochem 1979 Mar 05
PMID:Cytochrome P450 in adrenocortical mitochondria. 22 25

1. Human alpha1-antitrypsin was isolated from three Pi M and two Pi Z subjects without alteration of its microheterogeneity. The purified proteins were labelled with either 125I or 131I by a lactoperoxidase method. 2. The disappearance rate of two types of alpha1-antitrypsin were studied after simultaneous injection of labelled M-protein and Z-protein into Pi M subjects. 3. The ratio of extravascular to plasma pools of alpha1-antitrypsin ranged between 1-2 and 1-6 with no difference between M- and Z-protein. The mean fractional catabolic rates of M-protein and Z-protein were respectively 0-26 and 0-40 per day. 4. The difference in catabolic rate of Z- and of M-protein is too small to explain why the alpha1-antitrypsin content of the blood in Pi ZZ subjects is only 15% of that normally found in Pi MM subjects. The low alpha1-antitrypsin in Pi ZZ subjects appears mainly to be due to a low rate of biosynthesis.
Clin Sci Mol Med 1977 May
PMID:Catabolic rate of alpha1-antitrypsin of Pi type M and Z in man. 30 Oct 79

Compounds were studied that inhibit the oxidative degradation of human serum albumin by peroxidase and the enzyme model, iron hydroxide. Differences between the two oxidants gave clues for the mechanism of inhibition. The inhibitors studied were inorganic anions, phosphate, sulfate, carbonate and molybdate; organic anions, decanoate and glycocholate; and the nonionic species, glycogen. Such inhibitors might be considered as adjuvants in senescence: by decreasing the rate of enzymic oxidation of essential body proteins, they would, in the course of aging, reduce some of the physiological changes occurring as a result of accumulation of degraded protein.
Mol Biol Rep 1979 Feb 15
PMID:Inhibitors of oxidative degradation of protein: gerontological implications. 44 Feb 99

When histone is oxidized by peroxidase, its basicity (hence its complexing with DNA) is reduced: this reduction causes further alterations in the effect of histone upon the heat denaturation, acid precipitation, and breakdown by DNase of DNA, alterations which indicate that the regulation by histone of DNA expression may become abnormal. If oxidized species of histone should accumulate in the tissues in old age, the alteration mentioned might be a contributory factor of senescence.
Mol Biol Rep 1979 Dec 31
PMID:Histone: oxidation by peroxidase alters its interaction with DNA. 53 Feb 75

The particles of an iron hydroxide sol were found to be a suitable model for protein-oxidizing enzymes such as peroxidase and polyphenol oxidase. In addition to small molecules such as pyrogallol, human serum proteins, albumin and gamma-globulin, are shown to be substrates of the oxidizing model. The activity is markedly increased by the addition of small amounts of copper to the iron in the particles of the sol. The size and molecular weight of the enzyme model, as well as the number of active centers were determined.
Mol Biol Rep 1978 Jun 16
PMID:Iron hydroxide: model for enzymes that oxidize proteins. 68 84


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