Methenyltetrahydrofolate Cyclohydrolase Catalyzes the Synthesis of (6S)-5-Formyltetrahydrofolate

✍ Scribed by Joelle N. Pelletier; Robert E. MacKenzie

• Book ID: 102563853
• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 181 KB
• Volume: 24
• Category: Article
• ISSN: 0045-2068
• DOI: 10.1006/bioo.1996.0020

✦ Synopsis

The methenyltetrahydrofolate cyclohydrolase activity of the bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase domain catalyzes the conversion of 5,10-methenyltetrahydrofolate to 10-formyltetrahydrofolate. We have observed that in the presence of this domain, 10-formyltetrahydrofolate is converted to 5-formyltetrahydrofolate. The effects of nucleotide analogs on the initial rates of this reaction were found to be similar to their effects on the cyclohydrolase activity, establishing that 5-formyltetrahydrofolate production is dependent on the cyclohydrolase. The specific activity of 5-formyltetrahydrofolate production is approximately 7 ϫ 10 4 -fold lower than that of the cyclohydrolase activity but can be used to obtain quantitative conversion of 10-formylH 4 folate to 5-formyltetrahydrofolate, in mg amounts. This ''side-reaction'' may contribute to the in vivo production of (6S)-5formyltetrahydrofolate.