Characterization of two forms of cationic peroxidase from cultured peanut cells.

Two forms of cationic peroxidase from peanut cells were differentiated by concanavalin A affinity chromatography. They differed in molecular mass as well as concanavalin A binding, leading to the initial suggestion that they represented two isozymes of peroxidase. However, similar values for the specific activity, Soret absorption, calcium content, and peptide molecular mass were observed for each of the forms. Therefore, the binding and nonbinding fractions most likely represent two molecular forms of cationic peanut peroxidase, rather than two distinct cationic isozymes. The difference between these two forms is discussed in terms of glycosylation. Through the amino acid sequence analysis of the formic acid treated peptide, the cationic isozyme has been shown to be identical in amino acid sequence to the cDNA clone PNC1.