We have identified and purified to homogeneity an enzyme from rat liver that catalyzes the
oxidative catabolism of 5-formyltetrahydrofolate to p-aminobenzoylglutamate and a pterin
derivative. Purification of the enzyme utilized six column matrices, including a pterin-6-
carboxylic acid affinity column. Treatment of crude rat liver extracts with EDTA or heat
decreased the specific activity of the enzyme by up to 85%. Peptides generated from the
purified protein were sequenced and found to be identical to primary sequences present …