The identification of C-terminal amino acid of trichosanthin (T) of Trichosanthes kirilowii was 1st tried by chem. and enzymic methods such as hydrazinolysis, thiohydantoin reaction, and carboxypeptidase hydrolysis. Results were complicated by the possible presence of >1 terminus, i.e. methionine and alanine (Ala), and by side reactions with the chem. reagents. A computer-assisted carboxypeptidase method determine the C-terminal sequence of T. Its C-terminal sequence is heterogeneous and was identified as -ArgAsnAsnMetOH and ArgAsnAsnMetAlaOH. These 2 sequences were confirmed by other experiments In one, some free Ala was always in the CNBr degradation products of T. In the other, 2 fragments from the trypsin digest of T were isolated from fingerprints as well as from HPLC fractions and their sequences were determine by the DABITC/PITC manual method were the same as those determine by computer simulation.n

Key words: RADIX TRICHOSANTHIS, AMINO ACID SEQUENCE ANALYSIS, CARBOXYL PEPTIDASE, COMPUTER AIDED DESIGN, PROTEIN, GYNECOLOGIC AND OBSTETRICAL DISEASES