GLYCOGEN AS PRIMORDIAL CARBON RESERVE AND ALPHA-GLUCOSIDASE IN THE GENERA LYNGBYA-PHORMIDIUM-PLECTONEMA, THERMOPHILIC CYANOBACTERIA

This work was done to characterize the structure of a photosynthetic p olysaccharide and its metabolizing enzymes in cyanobacteria, which rep resent a link between bacteria and green plants in evolutionary terms. Filamentous cyanobacteria, occurring in an alkaline hot spring (45-50 degrees C, pH 8.5-9.0) in Kagoshima Prefecture, were morphologically classified in the genera Lyngbya-Phormidium-Plectonema (LPP), We found a thermostable neutral alpha-glucosidase with optimum pH 6.5 in the L PP, A polysaccharide isolated from the TCA-soluble fraction of the LPP was characterized as glycogen that resembled animal glgcogen in struc ture, We also recognized the presence of the TCA-insoluble glgcogen at 32-38% of the total amount of glycogen, most of which was bound non-c ovalently to protein and had a similar iodine absorption spectrum to t hat of the TCA-soluble glycogen.