Enzymes for synthesis of 10-formyltetrahydrofolate in plants. Characterization of a monofunctional 10-formyltetrahydrofolate synthetase and copurification of 5,10-methylenetetrahydrofolate dehydrogenase and 5,10-methenyltetrahydrofolate cyclohydrolase activities.

摘要: Plants require folates for the biosynthesis of purines, serine, methionine, formylmethionyl-tRNA and thymidylate (1). In leaves, mitochondrial mediate glycine cleavage serine formation during photorespiration (2). also have enzymes (1,3) that interconvert methylene-and formyltetrahydrofolates. Alternatively, these species generate 10-HCO-H4PteGlu from formate Recent work Rabinowitz’s laboratory (4,5) on latter reaction in spinach identified a monofunctional synthetase protein whose primary structure is like domain mammalian yeast trifunctional Cl-THF synthase. Partial purification related dehydrogenase cyclohydrolase activities suggested they may occur as bifunctional complex leaves (4). However, it not clear whether this structural organization typical higher plants general or reflect possible chloroplastic origin.