The present paper deals with investigations on the changes of water soluble proteins of the rice kernels in relation to the changes in ripening and during storage.
The proteins were extracted from rice kernels (10g) with distilled water (30cc) and after centrifugation (4,000r.p.m.-10min.), the supernatant (25cc) was concentrated with Visking seamless cellulose tubing against polyethylen glycol-1,500. Given conditions for paperelectrophoresis were 0.5 mA/cm current and 15～20 V/cm voltage in barbiturate buffer (pH 8.6 ionic strength 0.05) and the changes of the optical densities in that pattern were measured by Hitachi's densitometer after staining with 1 % B.P.B. ethanol solution and 0.5 % acetic acid solution.
In younger fruits of rice, even at 7 days after heading, 2 peaks in the pattern were clearly divided, though in the leaf extract, 1 peak was only found. At final stage of ripening (brown rice), 4 peaks were observed in the electrophoretic pattern. So far as this experiment was concerend, the water soluble proteins seem to be composed of 4 proteins in endosperm and 2 proteins in embryo and these peaks seem to disappeare in later storage.