Fig. 2.

Recombinant PPO proteins and enzyme activity. (A) Western blot analysis of insoluble (left panel), and soluble protein extracts (right panel) enriched and purified on a Ni-column. Protein extracts of 6h IPTG-induced E. coli cultures expressing His-tagged proteins were separated on a 12.5% SDS gel and detected by an anti-His-tag antibody: lacZ:his (120kDa), TpPPO1:his (59kDa, migrates at 65kDa according to Sullivan et al., 2004), PPO6:his (62kDa). (B) Specific PPO activity of enriched and purified soluble protein extracts determined polarographically using 4-methylcatechol as a substrate. Bar, standard deviation (n = 3).