A substance promoting the function of toad heart was obtained as an isoelectric precipitate by adjusting pH of the culture filtrate of Bacillus subtilis K to 3.0. The precipitate was purified by chromatography on DEAE-cellulose column and then gel chromatography on Sephadex G-75. The substance was finally isolated by column chromatography over acid alumina. It seemed to be homogeneous by electrophoresis on polyacrylamide gel disc. This substance was found to be a lipoprotein which was derived from the cytoplasmic membrane fraction of the vegetative cells according to immunological examination. This substance increased the 32P-uptake into chick myocardium 2 hr after intraperitoneal injection of 0.5 mg/chick.
