1. Dihydropteridine reductase and tetrahydropterin in Crithidia fasciculata cells.
- Author
-
Hirayama K, Nakanisi N, Sueoka T, Katoh S, and Yamada S
- Subjects
- Aminopterin pharmacology, Animals, Dihydropteridine Reductase antagonists & inhibitors, Methotrexate pharmacology, Molecular Weight, NAD metabolism, Substrate Specificity, Crithidia metabolism, Dihydropteridine Reductase metabolism, NADH, NADPH Oxidoreductases metabolism, Pterins metabolism
- Abstract
Dihydropteridine reductase was found in extracts of Crithidia fasciculata and was demonstrated by the fact that the enzyme required both quinonoid-dihydropterin and NADH as substrates. 7,8-Dihydropterin and dihydrofolate failed to serve as substrates; tetrahydropterin was formed as the reaction product. The molecular weight of the enzyme was estimated to be about 55 000 by Sephadex G-100 gel filtration. NADH was more effective than NADPH as substrate for the enzyme. Tetrahydropterin (1.35 nmol tetrahydrobiopterin equivalents/g cells) was also detected in C. fasciculata.
- Published
- 1980
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