Methemoglobin reduction in human red blood cell is governed by many factors, one of which is the concentration of oxyhemoglobin. Experiments were conducted to determine the inhibition of methemoglobin reduction by oxyhemoglobin under concentrations approaching those in the red cell. Hemoglobin, methemoglobin reductase and cytochrome b₅ were prepared by routine protein purification methods. Methemoglobin reduction was carried out at 37° C in spectrophotometer. It is shown that methemoglobin concentration variation (at least when it is above 1 mM) does not change the reduction rate. Whereas, the ratio of methemoglobin to oxyhemoglobin determines the rate of methemoglobin reduction when all other factors remain constant. It is concluded that in the red blood cell, significant increase of methemoglobin concentration alters the ratio of methemoglobin to oxyhemoglobin which in turn accelerates methemoglobin reduction.
"Methemoglobin Reduction in the Presence of Various Concentrations of Oxyhemoglobin,"
Journal of the Arkansas Academy of Science: Vol. 39
, Article 18.
Available at: http://scholarworks.uark.edu/jaas/vol39/iss1/18