TRICHOBITACIN - II - DETERMINATION OF THE PARTIAL PRIMARY STRUCTURE OF TRICHOBITACIN

Trichobitacin is a new ribosome-inactivating protein (RIP) isolated fr om the press-residue of the fresh root tube of Trichosanthes kirilowii Maxim, Cucurbitaceae. Its molecular weight is 27,228, and pI 9. 6. Fr om the mass peptides maps, determined by matrix-assisted laser desorpt ion ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and fas t atom bombardment mass spectrometry (FAB-MS) of trichobitacin and tri chosanthin digested by trypsin respectively, some corresponding peptid es have been found. Because both of trichobitacin and trichosanthin ar e isolated from the root tube of Trichosanthes kirilowii Maxim, they a re homologous, the amino acid sequences of the two proteins may be ver y similar, so these peptides may have similar sequences in two protein s. In addition to the results of protein N-terminal sequencer, the N-t erminal 38 amino acids sequence of the trichiobitacin has been determi ned, and more than 100 amino acids sequences have also been determined by the methods of protein automatic sequencer and manual DABITC/PITC double coupling as well as mass spectrometry respectively.