PTERINS OF THE CYANOBACTERIUM APHANIZOMENON FLOS-AQUAE

The cyanobacterium Alphanizomenon flos-aquae contains various glycosid es of a pterin that had previously been tentatively identified as 6-(t hreo-1,2-dihydroxypropyl)-pterin. The pterin is now identified as 6-(L -threo-1,2-dihydroxypropyl)pterin (6-L-threo-biopterin) by NMR and mas s spectrometry, thin layer chromatographic comparisons with authentic samples and by optical rotation. The 6-L-threo-biopterin glycoside-l f rom toxic strain NH-1 gave rise to xylose and glucose on hydrolysis, w hereas its glycoside-2 from Cambridge Collection and nontoxic NH-1 str ains gave mannose and glucose. This pterin may be a useful marker for certain species of cyanobacteria.