| Abstract: | SYNOPSIS. The carbohydrate which accumulates in the cytoplasm of the marine protozoon, Parauronema acutum, during normal growth was isolated, purified and characterized chemically. The highly purified material yielded only glucose residues following hydrolysis in 0.6 N HCl for 3 h at 100 C; measurement of total carbohydrate by the phenol-sulfuric acid method and by treatment with amylo-glucosidase and glucose oxidase gave similar values. Aqueous solutions of the purified material reacted with iodine to form a complex which exhibited an absorption peak at 456 nm with a shift to 484 nm in the presence of 50% saturated (NH4)2SO4. Digestion with α-amylase, β-amylase, and isoamylase yielded 71%, 45% and 8.3% hydrolysis, respectively. Treatment sequentially with both isoamylase and β-amylase gave complete hydrolysis of the polymer. The average chain length (CL) determined by the isoamylase procedure was 12. These observations are consistent with the view that the carbohydrate isolated from the protozoan is a polymer consisting of α-D-glucose residues arranged in chains containing α-(1→4) linkages with branch points containing α-(1→6) linkages occurring once on the average of ～ 12 glucose residues and, as such, is indistinguishable from glycogen isolated from mammalian sources. |
