NEW MATERIAL:The glycoprotein RBF-PGP obtained from the surface skin part of rice. Elemental analysis (%), C 53.0W56.0, H 7.80W8.50, and N 10.5W11.4; molecular weight, about 170,000 (by gelfiltration); isoelectric point, pH=4.7±0.15; solubility, insoluble in water, physiological saline water, dilute hydrochloric acid, etc., and soluble in dilute alkaline aqueous solution; color reaction, positive to biuret reaction, etc., and negative to phenol sulfuric acid reaction, etc.
USE: Antitumor agent exhibiting remarkable antitumor activity against the trasplanted carcinoma of experimental animal by oral administration.
PREPARATION: The objective RBF-pgp can be prepared by preparing RBF-P from the surface skin part of rice according to the method disclosed in the Japanese Patent Publication No.59-4690, extracting the RBF-P with a polar organic solvent, treating the soluble component under acidic condition with an organic solvent immiscible with water under dilute alkaline condition (e.g. hydrocarbons, ethers, etc.), and removing the component soluble in the organic solvent.
OTOMO TERUO
KAWAI KIMITOSHI
SAPPORO BREWERIES
ITO ETSUO