Isolation, characterization and expression of cationic peroxidase isozymes released into the medium of cultured tobacco cells
Narita, H. | Asaka, Y. | Ikura, K. | Matsumoto, S. | Sasaki, R.
Three glycoproteins of 34, 38 and 40 kDa were isolated from the spent medium of suspension-cultured tobacco cells. The 38-kDa and 40-kDa proteins were highly cationic peroxidases with indistinguishable enzymic properties but their structural difference was confirmed by sequence analysis of the amino-terminal regions and the recognition specificity of monoclonal antibodies. The 34-kDa protein was a moderately cationic peroxidase with enzymic properties quite different from those of the 38-kDa and 40-kDa enzymes. They were undetectable in the spent medium during the cell-proliferation phase but became abundant in the medium during the cell-expansion phase. This was confirmed quantitatively with the 40-kDa protein using the 40-kDa-specific monoclonal antibody. The mRNA expression for 40-kDa protein was at a constant basal level in the cell-proliferation phase but increased in the cell-expansion phase.Show more [+] Less [-]