Further Studies on N⁵-Formyltetrahydrofolic Acid Cyclodehydrase^*

Mechanism for the Coupling of ATP Hydrolysis to the Conversion of 5-Formyltetrahydrofolate to 5,10-Methenyltetrahydrofolate

“…The enzyme activity was first found in sheep liver acetone powder extracts by Peters and Greenberg (1) and later studied by Kay et al and Greenberg et al (2,3). This enzyme has been purified to homogeneity from both prokaryotic and eukaryotic sources (4 -6).…”

Cloning and Characterization of Mitochondrial 5-Formyltetrahydrofolate Cycloligase from Higher Plants

“…The heating step (30) was omitted. 5,10-CHϭH 4 PteGlu n was estimated from absorbance at 350 nm relative to a blank to which ATP was added after incubation; an extinction coefficient of 24,900 M Ϫ1 cm Ϫ1 was used (32). Continuous assays were run at 23°C in 50 mM MES-KOH, pH 6.0, using the ATP, Mg acetate, and 5-CHO-H 4 PteGlu n concentrations indicated; [Mg⅐ATP] was calculated as described (33).…”

Biochemical and Molecular Studies of Human Methenyltetrahydrofolate Synthetase

“…The product is then interconverted into the other one‐carbon substituted H 4 folates. MTHFS activity has been purified from sheep liver [40], Lactobacillus casei [41] and rabbit liver [42], and we have purified it from human liver as described below [43]. The primary amino acid structure and the 5‐formylH 4 folate polyglutamate binding site of rabbit liver MTHFS have recently been determined [44].…”