Polyphenoloxidase (PPO) activity in tea plant in Darjeeling, Assamica, Shooravi and 100 other varieties was examined quantitatively and qualitatively monthly and for a duration of one year. In the first three leaves on shoot the trend of the enzyme activity from spring to winter was ascending and increasing from the fist leaf to the third. Appearance of PPO bands of tea leaf on polyacrylamide gels (PAGE), with DL-DOPA, showed that the mentioned bands are of high molecular weight and concomitant with increase in enzyme activity from spring to winter, the number of PPO isoenzymes were increased. The results indicate a relationship between the quality of tea leaf and PPO activity as well as related isoenzymes.
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