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A double-headed trypsin inhibitor(MCI-1)was isolated and purified from the seedsof Momordica charantia Linn.Cucurbitaceae,by using the trypsin-sepharose-4B affinity chroma-tography and CM-Sephadex-C50 ion exchange chromatography.It is composed of 77 aminoacid residues:Asp_8 Thr_1 Ser_4 Glu_8 Pro_2 Gly_6 Ala_4 Cys_(14) Val_2 Met_4 Ile_8 Leu_1 Phe_1 His_3 Lys_ Arg_7.The amino acid sequence of MCI-1 was determined by sequencing the cyanogen bromide,tryptic andstaphylococcus aureus V8 proteolytic peptides,then aligned by overlapped sequences.The result showsthat MCI-1 contains 7 pairs of disulfide bonds,its sequence showed the high homology with those of“Bowman-Birk”inhibitors.About 50% trypsin inhibitory activity still remained after MCI-1 wascleavaged with cyanogen bromide.
A double-headed trypsin inhibitor (MCI-1) was isolated and purified from the seeds of Momordica charantia Linn. Cucurbitaceae, by using the trypsin-sepharose-4B affinity chroma-tography and CM-Sephadex-C50 ion exchange chromatography. It is composed of 77 aminoacid residues: Asp_8 Thr_1 Ser_4 Glu_8 Pro_2 Gly_6 Ala_4 Cys_ (14) Val_2 Met_4 Ile_8 Leu_1 Phe_1 His_3 Lys_Arg_7. The amino acid sequence of MCI-1 was determined by sequencing the cyanogen bromide, tryptic and staphylococcus aureus V8 proteolytic peptides, then aligned by overlapped sequences. The result showsthat MCI-1 contains 7 pairs of disulfide bonds, its sequence showed the high homology with those of “Bowman-Birk” inhibitors. About 50% trypsin inhibitory activity still remained after MCI-1 wascleavaged with cyanogen bromide.