A new procedure for the zymography of monophenolase and o-diphenolase activities of polyphenol oxidase (PPO), and peroxidase (POX) is proposed using a highly sensitive, chromogenic nucleophile 3-methyl-2-benzothiazolinone hydrazone (MBTH), which traps quinones. The procedure allowed the distinction between PPO isoenzymes from sorghum and mushroom in the same gel, as well as between monophenolase and o-diphenolase activities of PPO isoenzymes from crude extracts of mushroom. Three isoforms were detected with monophenolase activity, and at least seven isoforms were detected with o diphenolase activity. The procedure also allows the identification of PPO isoforms exhibiting monophenolase activity from a crude extract. The sensitivity, speed and ability to discriminate between mono and o-diphenolase activities could make the newly developed procedure a universal and powerful method for the routine zymography of PPOs and POXs in biological materials. The assay also discriminates the activities of PPOs, POXs and laccases.
- polyphenol oxidase,
- activity staining,
Available at: http://works.bepress.com/dicko/4/