Research Article

Peroxidase as the Major Protein Constituent in Areca Nut and Identification of Its Natural Substrates

Figure 3

Dimerization and glycosylation of the intact AN peroxidase. (a) Zymogram assay and (b) Coomassie staining. The enzyme was desalted with Tris/HCl buffer (20 mM, pH 7) (1) and HEPES buffer (20 mM, pH 7.9) (2). (c) Treatment of denatured AN peroxidase with PNGase F for 24 (2) and 48 h (3). The digested products, accompanied by the untreated control (1) and PNGase F itself (4), are indicated by arrowheads at the right. (d) PMF for the partially glycosylated intermediate (upper panel) and unglycosylated form (lower panel). Two tryptic peptides subjected to analysis are indicated by arrowheads with the sequences shown in each panel.