Primary Structure of the Nucleic Acid from the 1,4-α-Glucan Branching Enzyme

Abstract

The primary structure of the nucleic acid from the branching enzyme 1,4-.alpha.-glucan:1,4-.alpha.-D-glucan 6-.alpha.-D-(1,4-.alpha.-glucano)-transferase (EC 2.4.1.18; 2.5-S RNA) isolated from rabbit muscles was elucidated. The polyribonucleotide consists of 31 nucleotides; the unique features of the polyribonucleotide are the unusually high content of modified nucleotides (32%) and guanine residues (40%). Apparently 2.5-S RNA belongs to a class of nucleic acids unknown up to now. It is the first time that the structure of a nucleic acid component from a ribonucleoenzyme has been defined. Insight was gained into the intimate activating effect of the polyribonucleotide on the enzyme action.