Dehydrogenase Variants Research Articles

A Philippino Glucose-6-Phosphate Dehydrogenase Variant (G6PD Union) With Enzyme Deficiency and Altered Substrate Specificity

Abstract A variant of glucose-6-phosphate dehydrogenase (G6PD) associated with altered substrate specificity and severe deficiency of red cell enzyme activity was found in a Philippino male and in his relatives. The genetic pattern was consistent with X-linked inheritance. α-Thalassemia was found in the propositus and in several family members, but there was no interaction between G6PD deficiency and α-thalassemia. This G6PD variant has two pH optima, at pH 5.5 and pH 9.0, while the normal enzyme is inactive at pH 5.5. The substrate specificity of the variant enzyme is different from any known G6PD variant: 2-deoxyglucose-6-phosphate and galactose-6-phosphate are good substrates and deamino-NADP is a better coenzyme than NADP. Although G6PD activity in the variant red cells was only three per cent of normal, quantitative immunologic neutralization suggested that the specific activity of the variant enzyme might be at least ten per cent of that of the normal enzyme. This variant is named after the place of origin, Gd Union.

New glucose-6-phosphate dehydrogenase variants observed in Israel and their association with congenital nonspherocytic hemolytic disease.

Abstract Five cases of congenital nonspherocytic hemolytic disease were studied. In 3 of them, new glucose-6-phosphate dehydrogenase variants were detected while the common Mediterranean variant was found in the other 2. An additional variant was characterized from the blood of a patient who had a hemolytic episode during infectious hepatitis. No correlation was found between the characteristics of the variant enzymes and the clinical manifestations of the disease.

Isolation and purification of human erythrocyte glucose-6-phosphate dehydrogenase from small amounts of blood

1. 1. A simple procedure for the purification of glucose-6-phosphate dehydrogenase ( d-glucose-6-phosphate:NADP + oxidoreductase, EC 1.1.1.49) from 500 ml of human blood is described. 2. 2. The procedure consists of three main steps: DEAE-Sephadex chromatography; recycling gel filtration on Sephadex G-100; CM-Sephadex chromatography with specific elution by substrate. 3. 3. The enzyme, obtained with an overall yield of about 60%, has a specific activity of about 190 units/mg in diluted state, and it is shown to be homogeneous by electrophoresis on cellulose acetate gel and by N-terminal amino acid determination. 4. 4. The procedure is particularly suited for structural studies of rare glucose-6-phosphate dehydrogenase variants, but it can be scaled-up for the study of common glucose-6-phosphate dehydrogenase variants associated with low activity.

Rapid detection of 6-phosphogluconate dehydrogenase variants by electrophoresis on cellulose acetate gel.

A procedure, suitable even under “field conditions” for the rapid detection of 6-phosphogluconate dehydrogenase electrophoretic variants, is described.

Erythrocyte lactate dehydrogenase variants in the Icelandic and Swedish populations.

Erythrocyte lactate dehydrogenase variants in the Icelandic and Swedish populations.

Glyceraldehyde-3-phosphate dehydrogenase variants in phyletically diverse organisms.

Electrophoretically distinct forms of glyceraldehyde-3-phosphate dehydrogenase (TDH) have been detected in turtle, perch, trout, spinach, and yeast. Multiple forms were not detected in rat, rabbit, chicken, frog, honey bee, Euglena, or Escherichia coli. The combination of two different subunits into tetramers is a probable explanation for the five-membered sets usually detected in extracts exhibiting TDH multiplicity.

A lactate dehydrogenase variant in the mouse.

A GENETICALLY determined lactate dehydrogenase (LDH) variant has been demonstrated in the mouse, using starch-gel electrophoresis. After electrophoresis1, the sliced surface of the gel is incubated with lactate substrate.

Comparison of the Actions of Human Brain, Liver, and Heart Lactic Dehydrogenase Variants on Nucleotide Analogues and on Substrate Analogues in the Absence and in the Presence of Oxalate and Oxamate

Comparison of the Actions of Human Brain, Liver, and Heart Lactic Dehydrogenase Variants on Nucleotide Analogues and on Substrate Analogues in the Absence and in the Presence of Oxalate and Oxamate