Alberta M. Albrecht

Pteridines and the Nutrition of the Protozoon Crithidia fasciculata.

Summary The Trypanosomid flagellate Crithidia fasciculata was found to have a growth requirement for certain 6-substituted pteridines. The most active compound studied was 2-amino-4-hydroxy-6 (1′, 2′-dihydroxy-propyl) pteridine (“biopterin”) which was isolated from human urine. A requirement for both pteroylglutamic acid and an appropriate pteridine was demonstrated for the organism.

Evidence for occurrence of 10-formyltetrahydrofolic acid in human urine.

Summary Microbiological studies with Leuconostoc citrovorum, ATCC 8081 (Pediococcus cerevisiae) showed that a heat labile form of citrovorum factor (HLCF) occurs in the urine of normal adults after an oral dose of folic and ascorbic acids. Anhydroleucovorin (AHL) resembled HLCF in that AHL was active for growth of L. citrovorum (13% as active as leucovorin) when acid solutions were assayed aseptically, but neutral solutions of AHL were low in microbiological activity unless ascorbic acid was present. HLCF was purified by large scale paper chromatography which permitted a study of its chemical properties. The chemical relationships between 5CHOTHFA, AHL, and 10-CHOTHFA were discussed with regard to the chemical properties that were demonstrated for HLCF from which it was concluded that HLCF is probably 10CHOTHFA.