Bound and unbound pyridine dinucleotides in normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes.
We have measured, by a sensitive cycling assay, the concentration of bound and unbound dinucleotides in normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes. Measurement of free NADP in ultrafiltrates confirms that in normal erythrocytes almost all NADP is bound to cytosolic proteins. In glucose-6-phosphate dehydrogenase-deficient erythrocytes unbound NADP is significantly higher than in normal red cells and the NADP+/NADPH ratio is largely in favor of the oxidized form. In normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes essentially all NAD (bound and unbound) is in the oxidized state. About 50% of the total amount of NAD (NAD+ + NADH) is free in the cytosol, with a NAD+/NADH ratio greater than 100.
Canepa
L
L
Division of Hematology, University of Genova, ISMI, Italy.
Ferraris
A M
AM
Miglino
M
M
Gaetani
G F
GF
D003600:Cytosol / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000378:metabolism*; D006801:Humans; D008297:Male; D009243:NAD / Q000378:metabolism*; D009249:NADP / Q000378:metabolism*; D010084:Oxidation-Reduction
D009243:NAD; D009249:NADP