Kinetic studies on methemoglobin reduction by human red cell NADH cytochrome b5 reductase.

The intermediate hemoglobins which were produced by the partial reduction of methemoglobin with human red cell NADH cytochrome b5 reductase were fractionated by the preparative isoelectric focusing. These were found to be composed of alpha3+beta2+ and alpha2+beta3+ valency hybrids by the studies of absorption spectra and inositol hexaphosphate-induced difference spectra. Furthermore, the changes in these intermediate hemoglobins during reduction of methemoglobin by the enzyme were studied in the presence or absence of inositol hexaphosphate using the isoelectric focusing fractionation on Ampholine plate gel...