[An active 2.5S RNA-polysaccharide complex].

The information on the initial step of enzymatic reaction of 2.5S RNA isolated from muscle 1,4-alpha-glucane branching enzyme (EC 2.4.1.18), isomerase amylose, has been reported for the first time. The 2.5S RNA-polysaccharide (starch) complex was isolated and partly characterized. It was shown that the complex retains its integrity during precipitation with ethanol, gel-filtration on a Biogel P-150 column and electrophoresis but dissociates into RNA and starch upon fractionation on a DEAE-52 cellulose column. Treatment of the original preparation with RNAase fully reflects the complex formation: with a decrease in the RNA content in the original preparation that of the synthesized complex diminishes. The RNA-polysaccharide complex exhibits the properties of the branching enzyme; its enzymatic activity markedly exceeds that of the free RNA.