[A method of determining NADH-methemoglobin reductase activity using amino derivatives of o-benzoquinone].

Rate of methemoglobin reduction was increased in erythrocyte hemolysates in presence of 4-N-(p-sulfanilino)-5-methoxy-1.2-benzoquinone. Kinetic parameters of total reaction and of individual steps showed that the substance and other amino-derivatives of ortho-benzoquinone could be used for estimation of methemoglobin reductase activity.