Pteridines in blue green algae.

The presence of a remarkably high concentration of pteridiineS in the blue green alga, Anacystis nidulanis 5, wvas demonstrated by Forrest, van Baalen, and Myers in 1957 (2). A number of (lifferent pteridines were then isolated and ideentifie(l. These included 2-amino-4-hydroxypteridine, 2,6-diamino-4-hydroxypteridline (10), a yellow pteridine assigned the structure 2-aimino-4-hydroxv-6-propionvl-5,8 or 7,8-dihydropteridine (4), and a glucosidle of 2-amino-4hydrox--6-(dihydrox-prop-l ) pteridline (biopterin) (fig 1) (3). Subse(quetnt work has slhown that prol-