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L F Panchenko

Publications and source records attributed to L F Panchenko.

At least 55 records · Page 3Linked to original sources
PubMed1984

[Dehydrogenases of the pentose cycle in rat liver peroxisomes].

Subcellular distribution of NADP+-dependent dehydrogenases of pentose phosphate pathway (glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase) in rat liver was studied, using differential and isopycnic centrifugation. The enzyme activity was detected in the purified peroxisomal fraction as well as in the cytosol. Both dehydrogenases are localized in the peroxisomal matrix. Administration of a hypolipidaemic drug clofibrate increases the amount of both enzymes in peroxisomes. The putative functional role of pentose phosphate cycle dehydrogenases in peroxisomes is discussed.

Animals↗
PubMed1983

[Effect of clofibrate on the polypeptide content of a purified fraction of rat liver peroxisomes].

The effects of the hypolipaemic agent clofibrate on rat liver peroxisomes and of its "ghosts" obtained by solubilization of peroxisomal matrix peptides were studied by Na-DS polyacrylamide gel electrophoresis. Clofibrate significantly altered the amount of some peroxisomal polypeptides which is correlated with its effect on the enzyme composition of these organelles. The possibility of identification of polypeptides in gels with subunits of some peroxisomal enzymes (catalase, urate oxidase, components of fatty acid beta-oxidation chain, etc.) is discussed.

Animals↗
PubMed1983

[Effect of clofibrate on intracellular enzyme distribution in the rat liver].

The effect of chronic administration of a hypolipaemic agent--clofibrate--on the subcellular distribution of liver enzymes in male rats was studied. Clofibrate produced an increase in the number of peroxisomes and also enhanced the activity of aconitase and histidine: glyoxylate aminotransferase (HGA) in liver homogenate. Differential centrifugation of homogenate revealed an elevation of the relative amounts of catalase, HGA and isocitrate dehydrogenase in the soluble cell fraction in clofibrate pretreated animals. Clofibrate induced peroxisomal HGA but failed to alter the amounts of catalase, urate oxidase and isocitrate dehydrogenase in the particles. In both the experimental and control groups the activity of aconitase, malate dehydrogenase (NAD+), creatine phosphokinase and glutathione reductase was observed in mitochondrial fractions and was not detected in purified peroxisomes.

Animals↗
PubMed1981

[Interaction of D-Ala2-[Tyr-3,5-3H]enkephalin(5-D-Leu) with opiate receptors of rat brain].

Some kinetic features of D-Ala2-[Tyr-3.5-3H]enkephalin (5-D-Leu) binding to opiate receptors of rat brain were studied. It was shown that the Leu-enkephalin D analog interacts with the high and low affinity binding sites of opiate receptors, the equilibrium constants being equal to 0.71 and 8.4 nM, respectively. The rate constant for the label association with the high affinity binding sites in 2 . 10(8) M-1 min-1; those for the label dissociation from the opiate receptor binding sites with high and low affinities are 7.2 . 10(-3) and 0.16 min-1, respectively. Hence, the half-life time of these complexes is 95.7 and 4.3 min, respectively. Na+, K+ and Li+ markedly decrease the specific finding of the label, while Mg2+, Mn2+ and Ca2+ at the concentrations studied markedly increase its specific binding. It is concluded that the Leu-enkephalin D-analog under study acts as a morphine agonist and reveals a much higher affinity for rat brain opiate receptors than does Leu- or Met-enkephalin. This makes it a useful tool for study of the enkephalin reception under normal and pathological conditions.

Animals↗
PubMed1980

[Effect of apomorphine on rat brain opiate receptors].

Stereospecific binding of apomorphine to rat brain opiate receptors was shown by assaying the competition of 7,8(n)--3H--naloxone and D-ala2-tyrosyl-3,5-3H--enkephalin (5-D-leucine) for opiate receptor binding. EC-NaCl50, the concentration of apomorphine which inhibited 50% binding of the radioactive naloxone and D-ala2, D-leu5-enkephalin in the absence of NaCl were 20 and 42 microM, respectively. EC+NaCl 50, the concentration of apomorphine which inhibited 50% binding of the radioactive naloxone in the presence of 100 mM NaCl was 17 microM. From the ratio of EC+NaCl 50 to EC-NaCl the value of "sodium shift" of effective concentration can be calculated as 0.85. From the data obtained it is concluded that apomorphine, like naloxone, is a "pure" antagonist but it has much less affinity for enkephalin and opiate binding sites. The probable mechanisms of the pharmacological action of apomorphine are discussed.

Animals↗
PubMed1976

Properties of the 3-o-methyl-D-glucose transport system in Acholeplasma laidlawii.

Transport of 3-O-methyl-D-glucose (3-O-MG) by Acholeplasma laidlawii cells was studied. The 3-O-MG transport system appeared to be constitutive in cells grown on 3-O-MG and glucose; the transport process depended on the concentration of substrate used and exhibited typical saturation kinetics, with an apparent Km of 4.6 muM. 3-O-MG was transported as a free carbohydrate and was not metabolized further in the cell. Dependence on pH and temperature and the results of efflux and "counterflow" experiments demonstrated the carrier nature of the transport system. 6-Deoxyglucose and glucose competitively inhibited 3-O-MG transport, whereas maltose inhibited in non-competitively. p-Chloromercuribenzoate, p-chloromercuribenzene sulfonate, N-ethylmaleimide, and iodoacetate inhibited transport of 3-O-MG. Cells were able to accumulate 3-O-MG against a concentration gradient. Some electron transfer inhibitors (rotenone and amytal), arsenate, dicyclohexylcarbodiimide, and proton conductors such as 2,4-dinitrophenol, carbonylcyanide, m-chlorophenylhydrazone, pentachlorophenol, and tetrachlorotrifluoromethylbenzimidazole inhibited this process.

Acholeplasma laidlawii↗
PubMed1976

[The influence of natural inhibitors of radical reactions on autooxidation of adrenaline].

In the presence of EDTA soluble antioxidants (1 muM reduced glutathion, 3 muM cystein, 1 muM ascorbic acid) inhibited the autoxidation of epinephrine at pH 10.2; as to alpha-tocopherol (40 muM) and the oxidative forms of these antioxidants - they were ineffective. The inhibitory effect of superoxide dismutase was much greater than that of the antioxidants testsd. The appearance of adrenochrome during the free radical autoxidation of epinephrine proceeded without any participation of the hydroxyl radical.

Antioxidants↗
PubMed1975

Transport properties of membrane vesicles from Acholeplasma laidlawii. I. Isolation and general characteristics.

A new procedure for the isolation of membrane vesicles from Acholeplasma laidlawii cells is described. The membrane vesicles are completely free from contaminations of whole cells and cell debris and represent a homogeneous fraction as shown by electron microscopy, Ficoll density-gradient centrifugation, and titration on agar plate. Absence of cytoplasmic contaminations was confirmed by double-labelling of membranes with 3H-oleic acid and 14C-uridine, as well as by distribution of specific marker enzymes of membranes and cytoplasm. On the basis of light-scattering and electron microscopy, the vesicular nature of these membranes was established. The vesicles had the same orientation as intact cells (absence on membrane vesicles of ATPase and NADH dehydrogenase activities, localized in the inner surface of membrane). The respiratory activity of the membrane vesicles was low and was not stimulated by exogenous substrates, the respiratory chain of the vesicles being reduced and terminated by flavoproteins. The ability of membrane vesicles to take up carbohydrates was shown.

Acholeplasma laidlawii↗
PubMed1975

Transport properties of membrane vesicles from Acholeplasma laidlawii. II. Kinetic characteristics and specificity of glucose transport system.

The glucose transport system of membrane vesicles isolated from Acholeplasma laidlawii is saturable, with a Km of 21.2 mum and V of 0.68 nmol min-1 (mg protein)-1. The process is pH-dependent and a break occurs in the Arrhenius plot at 15 degrees C. Exogenous substrates did not stimulate glucose transport probably due to their inability to penetrate into membrane vesicles. 3-O-Methylglucose and 6-deoxyglucose competitively inhibited glucose transport. Maltose inhibited transport of glucose noncompetitively. These sugars also elicited glucose efflux from preloaded membrane vesicles.

Acholeplasma laidlawii↗