Abstract
Publisher Summary This chapter discusses the role of formyl-methenyl methylenetetrahydrofolate synthetase protein in eukaryotic folate metabolism. Formyltetrahydrofolate synthetase (EC 6.3.4.3), methenyltetrahydrofolate cyclohydrolase (EC 3.5.4.9), and methylenetetrahydrofolate dehydrogenase (EC 1.5.1.5) have been demonstrated in a variety of bacterial, plant, and animal sources. The most highly purified preparations of the synthetase and dehydrogenase have been obtained from the bacterial sources as distinct proteins and do not appear to be physically associated with one another. The three activities involved in the interconversion of one-carbon adducts of tetrahydrofolate (THF) appear to be associated, with a single homogeneous protein, that catalyzes all three reactions in ovine liver, yeast, and probably in porcine liver. The three enzymic activities of the trifunctional protein can all be assayed, by spectrophotometric measurement of methenyl-THF, either directly in the assay mixture or after acidification. Activity is expressed in standard units of micromoles of methenyl-THF formed or hydrolyzed per minute calculated from the extinction coefficient of 24,900 M –1 cm –1 . The chapter describes the activity of trifunctional protein. A discussion on formyl-THF synthetase, methenyl-THF cyclohydrolase, and methylene-THF dehydrogenase is also discussed in the chapter.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
