Deficient Activity of DPNH-dependent Methemoglobin Diaphorase in Cord Blood Erythrocytes

Activity of DPNH-dependent methemoglobin diaphorase was measured in the erythrocytes obtained from 54 cord bloods and 54 adult controls. There was a significantly lower mean level for this enzyme in the cord bloods and the defect was occasionally severe. Mean diaphorase values of smaller infants was less than that of larger infants, suggesting a greater degree of metabolic immaturity in the former group, even in the absence of prematurity. This transient deficiency of methemoglobin diaphorase is probably a major cause for the increased susceptibility of young infants to the development of acquired methemoglobinemia.