1997 年 61 巻 1 号 p. 118-123
When suspension cells of French bean (Phaseolus vulgaris L. cv. Goldstar) were cultured in Murashige and Skoog (MS) liquid medium containing 10-6 M 1-naphthaleneacetic acid (NAA) and 10-6 M 6-benzylaminopurine (BAP) (control medium), endopeptidase activity was expressed throughout the cell growth. In the medium containing 10-5 M gibberellic acid (GA3), the endopeptidase activity increased notably during the cell culture, but in the medium containing amino acids the activity decreased. Protein immunoblotting with an antiserum raised against a French bean cysteine endopeptidase (EP-C1) showed that a 34-kDa polypeptide corresponding to EP-C1 in molecular mass occurred in extracts from cultured cells. Five forms of endopeptidase in extracts of cells cultured in the control medium and the four forms in the medium containing GA3 were detected by activity staining after non-denaturing polyacrylamide gel electrophoresis. Experiments with various protease inhibitors indicated that a serine endopeptidase was expressed at high levels in cultured cells in the control medium and the activity of a cysteine endopeptidase was increased by GA3.