The primary structure of trichosanthin has been revised by sequencing its peptides isolated by reverse-phase HPLC from the tryptic digest of the intact trichosanthin as well as by kinetic studying on the carboxypeptidease (CpA, CpB and CpY) degradation of trichosanthin and of CB-1, the CNBr-degrdn. fragment of trichosanthin. The revised amino acid sequence consists of 246(7) residues, the same as those reported by Collins (1990) except there was microheterogeneity at the C-terminus. No difference has been shown from the studies of the amino acid sequence of trichosanthin from different places of origin, Wuhu in Anhui province and Pinghu in Zhejiang province.

Key words: AMINO ACID SEQUENCE ANALYSIS, ANTITUMOR DRUGS, RICHOSATHIN PROTEIN, RIMARY STRUCTURE, IBOSOME-INACTIVATING PROTEIN