ABSTRACT
Determination of the complete amino acid sequence of HRP-C was largely contributed by Welinder (21). HRP-C consists of 308 amino acid residues, a hemin group, and eight neutral carbohydrate side chains attached to asparagine residues. The amino acid sequence and carbohydrate attachment points are shown in Figure 1. The molecular weight was reported to be between 40,000 and 45,000, and the carbohydrate moiety constitutes 18%. HRP-C is the most extensively investigated isoenzyme in the plant peroxidase superfamily. Within the superfamily, HRP-C belongs to Class III of the plant extracellular peroxidases (22). Peroxidases from flowering plants have considerable identity of amino acid sequences (40-64%). In particular, those sequences in the regions of the two His residues (the distal His42 and proximal His170 in HRP) and Cys residues forming disulfide bonds are conserved (12, 22).
