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Biomedical subjects

N B Cherniak

Publications and source records attributed to N B Cherniak.

At least 19 recordsLinked to original sources

[Detection of a new anomalous variant of glucose-6-phosphate dehydrogenase in human erythrocytes].

Kinetic and electrophoretic properties of 230--300 fold purified preparations of glucose-6-phosphate dehydrogenase (G6PD) from red cells of donors and patients with acute drug hemolytic anemia due to G6PD deficiency were studied. A new abnormal variant of G6PD isolated from red cell of a patient with acute drug hemolytic anemia, which was not described in literature, has been discovered. The abnormal enzyme differs from the normal by decreased Michaelis constant for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate (NADP), by increased utilization of analogues of substrates--2-deoxy-glucose-6-phosphate and particularly deamino-NADP, by low thermal stability, by the character of pH-dependence, by the appearance of a single band of G6PD activity in polyacrylamide gel electrophoresis.

Catalysis↗

[Kinetic properties of partially purified glucosephosphate dehydrogenase of human erythrocytes].

Partially purified glucose-6-phosphate dehydrogenase was isolated from small amounts of human erythrocytes (15-20 ml). The Km value for glucose-6-phosphate was 35.0 +/- 3.0 micronM, the Km for NADP was 4.27 +/- 0.3 micronM. The optimal activity of the enzyme was at pH 9.0. Glucose-6-phosphate dehydrogenase, dialyzed in presence of 1-10(-5) M NADP, had critical temperature about 52 degrees within 10 min of incubation; without NADP it was at 45 degrees. The method for isolation and purification of the enzyme was modified.

Adult↗

[Electrophoretic and kinetic properties of the erythrocyte glucose-6-phosphate dehydrogenase of patients with hemolytic anemia related to a deficit in the activity of that enzyme].

Partially purified glucose-6-phosphate dehydrogenase (G6PD) was studied in erythrocytes of patients with hereditary hemolytic anemia. Kinetic and electrophoretic properties of G6PD distinctly varied both in patients--homozygotes and in maternal heterozygotes. All the enzymes studied together with the decreased activity possessed the reduced Km value for NADP and G6P. Anomalous enzymes were shown to differ from normal ones by several patterns (pH-dependency, thermostability, % of the substrate analogues utilization, electrophoretic mobility etc). The mutant variant of G6PD was not described earlier. The anomalies variant was called "Kremenchug" to indicate the place of proband origination.

Chemical Phenomena↗

[Relationship between glycolysis and pentose cycle intensity and thrombocyte aggregation induced by ADP in man].

Aggregation of thrombocytes, caused by ADP, affected the rate of anaerobic breakdown of carbohydrates due to inhibition of the glucose degradation, while the rate of lactate formation was not distinctly altered. Content of NAD was decreased simultaneously with an increase in content of NADP; the activity of glucose-6-phosphate dehydrogenase was distinctly increased but the unaltered activity of 6-phosphogluconate dehydrogenase was observed; content of reduced glutathione was increased 15-fold. The activity of NADP-dependent glutathione reductase was increased under effect of ADP; at the same time, the activity of NAD-dependent glutathione reductase did not depend on the diphosphate effect.

Adenosine Diphosphate↗