Pteridine reductase (TbPTR1), isolated from Trypanosoma brucei, is an NADPH-dependent short-chain reductase. TbPTR1 has broad specificity and can catalyse the reduction of biopterin to 5,6,7,8-tetrahydrobiopterin (THB) and folate to tetrahydrofolate. Both these reactants can be reduced from the oxidised or dihydro-state since the mechanism is a two step reduction by two molecules of NADPH. These reactions are important for the salvage of pteridines from the host and so TbPTR1 is a potential drug target for the treatment of African trypanosomiasis.
TbPTR1 is a member of the Short-chain dehydrogenase/reductase (SDR) superfamily.