Proteinaceous substance showing antitumorous action and its preparing method

Claim 1

A proteinaceous substance having the following biochemical characteristics: (A) said substance has a high tumor specificity as evidenced by its strong cytolytic activity against mouse tumor cells L-929 and L-1210, and human carcinoma HeLa cells, and lack of cytotoxic activity against normal human fetus fibroblasts, normal human adult skin fibroblasts or normal Chinese hamster fibroblasts (Don, V-79); (B) said substance has a strong anti-tumor activity against Meth-A sarcoma, as evidenced by the fact that when said substance is administered intravenously to syngeneic BALB/c mice inoculated with Meth-A sarcoma at a quantity of more than 72 units/head, hemorrhagic necrosis of the tumor is observed, and subsequent successful implantation of Meth-A sarcoma cells in the same mice is not observed because of acquired immunity; (C) said substance has no pyrogenic effect on rabbits after intravenous injection; (D) said substance has a molecular weight of 45,000 plus or minus 5,000 as determined by gel filtration with Sepharcryl S-200; (E) said substance has an isoelectric point of 4.8 plus or minus 0.3; (F) said substance is sensitive to tyrpsin, but stable to heating at 56° C. for 30 minutes; (G) said substance is not glycosylated; and (H) said substance contains the following first 15 N-terminal amino acids: ##STR2## (I) said substance contains the following amino acid content: TABLE ______________________________________ Amino Number of Amino Number of Amino Number of Acid Residues Acid Residues Acid Residues ______________________________________ Asn 15 Ala 12 Phe 6 Thr 6 Val 16 Lys 9 Ser 10 Met 1 His 3 Gln 20 Ile 5 Arg 3 Pro 9 Leu 21 Cys 2 Gly 10 Tyr 8 Trp 2 Total 156 ______________________________________