The NADP-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase is not expressed in Spodoptera frugiperda cells.

摘要: Abstract The insect cell line derived from Spodoptera frugiperda (Sf9) does not express the activities of trifunctional NADP-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase-formyltetrahydrofolate synthetase. lack synthetase activity was confirmed by inability to incorporate radiolabeled formate into nucleotides. cells express, instead, a Mg2+ and NAD-dependent bifunctional cyclohydrolase with properties similar enzyme found in mitochondria transformed mammalian cells. In contrast, Sf9 is localized cytoplasm. Nutritional studies defined medium dialyzed serum demonstrated that required added purines or pyrimidines for growth. It auxotrophic cysteine glycine; this latter requirement probably due absence mitochondrial serine hydroxymethyltransferase. Incorporation labeled glycine DNA indicates only source one-carbon units. These results suggest do play major role folate-mediated metabolism.