Regulation of Polyphenol Oxidase in Higher Plants
The enzyme polyphenol oxidase (PPO) may be the most primitive, nonspecific defense system found in eukaryotes. In plants, it is responsible for the browning of damaged tissues as seen in apple, banana, and potato. It has been estimated that half the world's fruit and vegetable crop is lost due to the post-harvest browning reactions involving PPO. In plants and animals, PPO is nuclear encoded and transited to a cytoplasmic organelle (such as chloroplasts in higher plants). Presently, we are attempting to isolate and characterize an endogenous inhibitor of PPO which eventually, via various genetic and biochemical approaches, may help increase the storage life of fruits and vegetables.
Other interests are redox activity associated with the plasma membrane of plant cells and assimilatory sulfate reduction in algae.
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