Open AccessDihydropteridine Reductase
Author(s) -
Nielsen K. H.,
Simonsen V.,
Lind K. E.
Publication year - 1969
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1969.tb00636.x
Subject(s) - cofactor , reductase , peroxidase , enzyme , chemistry , biochemistry
The activity of the enzyme dihydropteridine reductase, which catalyses the reduction of quinoid dihydropteridine cofactor in the presence of NADH or NADPH, was measured in a system containing H 2 O 2 and peroxidase. Peroxidase and H 2 O 2 continually reoxidize the reduced tetrahydropteridine cofactor to the quinoid dihydropteridine cofactor, and thus maintains the concentration of the latter virtually constant. A method for calculation of the actual concentration of dihydropteridine cofactor and for correction of the dihydropteridine reductase activity to allow for variations in the dihydropteridine cofactor concentration have been derived. Even though dihydropteridine reductase can utilize either NADH or NADPH as the reductant, the former is 15 to 45‐fold more active than the latter. This specificity for the nucleotide cofactor has been found for dihydropteridine reductases prepared from five differnt mammalian species.