Abstract:
Polyphenol oxidase (PPO) from Zyzyphus spina christi found in central part of Iraq was extracted and
purified by (NH4)2SO4 precipitation, ion-exchange chromatography and gel filtration chromatography.
The biochemical characteristics reveal that the PPO from Zyzyphus spina christi has higher affinity towards
catechol (KM = 11.4mM and Vmax = 16,400 U/ml min ) at an optimum pH of 5.8. The enzyme had an optimum
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temperature of 37°C and was relatively stable up to 50°C for a period of 60 minutes with almost 80% activity
remaining. Among the various PPO inhibitors tested, the most effective inhibitor for the enzyme with 10mM
catechol as substrate was ascorbic acid.
