Über das Vorkommen und den Stoffwechsel von Biopterin

Abstract
Three biopterin-active substances were found in cell-free extracts of plants and microorganisms, none of which was identical with biopterin. Crithidia fasciculate did not change biopterin-[2-Cl4] into folic acid; Eremothecium ashbyii did not change folic acid-[2C 14 ] into biopterin.