A Reproducible Periodate Oxidation Method for the Determination of Glycogen End-Groups FRANK W. FALES Department of Biochemistry, Emory University, Atkanfa,
b The purpose of this investigation was to devise a simple and reproducible method for the determination of glycogen end-groups in the hope of facilitating comparative studies of the structure of various glycogens. The periodate oxidation method was the outgrowth of this work. The oxidation is carried out with 0.1M sodium metaperiodate for 48 hours a t about 3 ' C. A methyl-a-D-glucoside standard is included with each run to compensate for small changes in the experimental conditions which unavoidably occur during the long oxidation period. The precision of the determination is thereby greatly enhanced. The determination is based on the relative volumes of alkali required to titrate the formate released from the glycogen and from the standard, and upon the relative concentrations of the glycogen and of the standard determined by the anthrone method. About 50 mg. of glycogen are required for duplicate determinations. A difference in average chain length of 0.5 glucose unit can be distin0.05) with six replicate guished (P determinations.
