Incidence of variants of human red cell NADH diaphorase in Japanese newborns and coordinate developmental changes of its activity with fetal hemoglobin and F cells.

615 human newborns were examined for detection of polymorphism of red cell NADH diaphorase by isoelectric focusing on polyacrylamide gels. Although the incidence of variant forms among Japanese is about 0.46%, no variants were encountered in newborns. Enzyme activity of red cell NADH diaphorase from newborns was less than half of that from adults. There were no differences in enzyme activity between premature and full-term newborns. Increase of enzyme activity during development after birth was admitted in parallel with decrease of fetal hemoglobin (Hb F) content and also with reduction of F cells (which produce only Hb F) number.