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 myoglobin-like haemoprotein leghaemoglobin (Lb I) from lupine root nodules has a great affinity to molecular oxygen and seems to be involved in O2-transport. Some ligands of low molecular weight are supposed to affect the haemoglobin (Hb) and myoglobin (Mo) function in O2-transport. To investigate this possibility for lupine Lb I, the affinity of this protein to cyanide (CN-), azide (N3-), fluoride (F-), thiocyanate (NCS-), imidazole (Im), nicotinic acid (NA), acetic acid has been investigated, using: 0.05 M MES, pH 5.2-6.5; 0.1 M Na-phosphate in 0.05 M Tris-buffer, pH 6.5-9.0. The affinity for Lb I to N3-, CN-, F- and NA (the Bohr effect) was found to be pH-dependent. The values of PK ionization for the groups affecting the ligands binding were determined. The positive correlation between the ligand affinity and the ligand power was found. Lb I appears to have the greatest ligand affinity constants when compared with other haemoproteins of this class.
Mol Biol (Mosk)
PMID:[Lupine leghemoglobin affinity to ligands. The effect of pH and buffer nature]. 3 94

The condition of methylviologen photoreduction by chloroplasts was investigated. Argon bubbling through the suspension of chloroplasts or degasing in vacuum caused inhibition of methylviologen reduction probably due to the denaturation of chloroplast membranes at the water/air boundary. Adding glycerol or bovine serum albumine or removing oxygen from chloroplast suspension with the aid of the oxygen absorbing-systems preserved the activity of chloroplasts. Methylviologen photoreduction is inhibited by DCMU (10(-7) M) and Tris-buffer treatment and is activated by uncouples. The pH-dependence is similar to that of the Hill reaction. Triton X-100 (0.007%), ethyl ether (2%) and heating up to 42 degrees activated the Hill reaction but inhibited methylviologen reduction. Water molecule probably acts as an initial electron donor in this reaction. It is proposed that the steady level of methylviologen photoreduction is determined by a relationship between the rate of methylviologen electron acceptance and cyclic electron flow short-circuiting photosystem I.
Mol Biol (Mosk)
PMID:[Methylviologen photoreduction by chloroplasts]. 3 95

Heart and skeletal muscle from rats of different ages were incubated in vitro in an oxygen-free medium supplied with substrates in order to investigate the effect of anoxia on muscle fine structure, particulary on the mitochondria. In skeletal muscle fibers anoxia has been found to induce changes similar to those previously described in ischemic muscles in vivo namely giant mitochondria, apparently derived by mitochondrial fusion, and intermembrane inclusions with a paracrystalline structure. The plate-like inclusions are mostly located in the intracristal spaces and are closely associated to cristal membranes even in markedly swollen mitochondria. Identical inclusions have been observed in cardiac muscle cells following anoxic injury, whereas they are never found in non-muscle cells such as endothelia, fibroblasts and nerve fibers. Cardiac and skeletal muscle fibers from newborn rats maintained in an oxygen-free medium show mitochondrial swelling but no intermembrane inclusions. The different response of mitochondria from developing vs adult striated muscle to anoxia may be due to changes during postnatal development in the quality or quantity of the protein component(s) involved in paracrystal formation.
Virchows Arch B Cell Pathol Incl Mol Pathol 1979 Oct
PMID:Intermembrane inclusions induced by anoxia in heart and skeletal muscle mitochondria. 4 13

In the last few years much attention has been dedicated to the elucidation of some of the molecular aspects of cytochrome c oxidase. It has been shown conclusively that the enzyme from several sources (yeast, Neurospora, heart, liver) contains seven different subunits, which are asymmetrically inserted in the membrane. All of these are in contact with the lipid bilayer (except subunits V and VI) and to a greater or lesser extent with the water phase as well (except for subunit I). Subunit II of the enzyme appears to be involved in the formation of the binding site of cytochrome c. The location of the redox groups of the enzyme is still a matter of controversy. Their distance from the cytochrome c heme group is approximately 35 A such that electron tunneling appears to be the only possible mechanism for transporting electrons across such a distance. A proton pump appears to be associated with electron transport and approximately one proton is extruded per electron equivalent reducing oxygen via the enzyme. N,N', dicyclohexylcarbodiimide a well-established inhibitor of H+-translocating ATPases inhibits the proton pump and labels specifically subunit III of the enzyme.
Mol Cell Biochem 1979 Dec 14
PMID:Molecular aspects of cytochrome c oxidase: structure and dynamics. 4 69

Glucose stimulates the uptake of 45Ca into beta-cell-rich pancreatic islets isolated from ob/ob-mice. The distribution of the incorporated radioactivity was analysed by labelling the organelles with 45Ca in their cellular environment. The radioactive content of the organelles was measured after homogenization and fractionation of the islets under conditions preventing 45Ca redistribution. The 45Ca taken up in response to glucose appeared essentially in the secretory granule fraction and in that enriched in mitochondria. Modification of the 45Ca loading procedure, involving reduction of the oxygen tension and incubation volume, resulted in the disappearance of the glucose effect on the mitochondrial fraction whereas part of the stimulatory effect on the secretory granules persisted. Buffering of calcium by the secretory granules and mitochondria may be important for regulating the cytoplasmic Ca2+ involved in stimulus-secretion coupling.
Mol Cell Endocrinol 1979 Dec
PMID:Calcium and pancreatic beta-cell function. 6. Glucose and intracellular 45Ca distribution. 11 64

1. Rats kept in a hypoxic chamber (10% O2) for 3 or more weeks developed right ventricular hypertrophy, muscularization of pulmonary arterioles and polycythaemia. These changes resemble those found in human hypoxic disease and, in particular, in patients dying from chronic airways obstruction. 2. Resolution of these changes was studied in a normal environment and in an intermittently normal, intermittently hypoxic environment. The latter regimen modelled the situation of patients with cor pulmonale receiving long-term intermittent oxygen therapy. 3. In a normal environment right ventricular hypertrophy and polycythaemia were resolved in 6 weeks but vessel changes were not resolved in 12 weeks. 4. In the intermittently normoxic environment (40 or 80 h in air per week) there was some resolution of right ventricular hypertrophy in 6 weeks but no significant reduction in vessel thickening or in polycythaemia in 12 weeks.
Clin Sci Mol Med 1977 Feb
PMID:Resolution of hypoxic changes in the heart and pulmonary arterioles of rats during intermittent correction of hypoxia. 13 24

The ochre mutant oc9 of bacteriophage phiX174 was irradiated with gamma-rays and the revertants were assayed on unirradiated and UV-irradiated host bacteria carrying an amber suppressor. The yield of revertants (amber + wild type) was higher on UV-irradiated than on unirradiated bacteria, showing that gamma-irradiated phiX174 was subjected to W-mutagenesis. For oc9 gamma-irradiated in the presence of oxygen the fraction of amber mutants among the revertants was lower when mutants were scored on UV-irradiated bacteria than when assayed on unirradiated indicator cells. The same fraction of ambers was obtained when mutants were assayed on unirradiated and UV-irradiated samples of a recA indicator strain. UV-irradiated phiX174 showed a similar phenomenon. These results suggest that the specificity with regard to insertion of bases opposite radiation damage in phiX174 DNA is different for host cells in which SOS repair has been induced and cells in which SOS repair is not operative.
Mol Gen Genet 1979 Oct 03
PMID:Influence of SOS repair on the specificity of radiation mutagenesis in bacteriophage phiX174. 16 Sep 72

The splanchnic-hepatic metabolism of glucose, lactate, pyruvate, alanine, glycerol, non-esterified fatty acids (NEFA), ketone bodies and oxygen were investigated in five normal men and six juvenile diabetic subjects at rest and during exercise after an overnight fast. A linear relationship was found between load (arterial concentration multiplied by hepatic blood flow) and splanchnic-hepatic uptake of lactate, pyruvate, glycerol and NEFA. The uptake of alanine was highly sensitive to load, but was also regulated by the concentration of hepatic venous glucagon. The uptake of pyruvate was high in exercising diabetic subjects, who had a high lactate/pyruvate concentration ratio in hepatic venous blood. The rate of uptake of the total measured gluconeogenic precursors was significantly higher in the diabetic group at a given load. The rate of ketogenesis was linearly related to the NEFA load in both groups; however, the rate of ketogenesis was twofold at a given load in the diabetic group. The highest rates of ketogenesis were found coincident with the highest concentrations of glucagon in hepatic venous blood. The observed antiketogenic effect of exercise was due to a decreased load of NEFA, mainly caused by a decrease in the hepatic blood flow.
Clin Sci Mol Med 1977 Nov
PMID:Regulation of gluconeogenesis and ketogenesis during rest and exercise in diabetic subjects and normal men. 20 21

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

This reviews summarizes our evidence suggesting that the plasma protein enviroment influences platelet aggregation potential and metabolic activity. Cationic proteins are capable of restoring the aggreation potential of washed human platelets. The aggregation restoring effect of gamma globulin is inhibited by more anionic proteins in subfractions of Cohn fraction IV and fractions V and VI. Artificial enhancement of the net negative charge of plasma proteins through acylation produces derivatives capable of inhibiting platelet rich plasma. The oxygen consumption of washed human platelets is lower than in platelet rich plasma while the lactate production is identical. Autologus plasma, albumin or IgG immunoglobulin restores the oxygen consumption of washed platelets to values comparable to those obtained for platelet rich plasma, while the lactate production is unaffected. Fibrinogen on IgA myeloma protein increases the lactate production, but not the oxygen consumption. Cyclic AMP levels are considerably lower in washed platelets than in platelet rich plasma. Gamma globulin and albumin causes a futher decrease, which is progressive with time. Fibrinogen causes no change in platelet cyclic AMP content. It is suggested that these observations may in part be explained by the equilibriun between anionic and cationic proteins in the platelet microenvironment. This hypothesis appears applicable in certain situations.
Mol Cell Biochem 1979 Apr 02
PMID:Plasma protein regulation of platelet function and metabolism. 22 26


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