Abstract :
Browning of damaged tissues in fresh fruits and vegetables results mainly from the
oxidation of phenolic compounds to quinones by polyphenol oxidase (PPO). The
activation of PPO by sodium dodesyl sulphat investigated, but reports on the effect
of detergents and chaotropic agents on activity of PPO are scarce. Here the effect of
some detergents and chaotropic agent on activity of enzyme in soluble and in
partial purified fraction was investigated. Sarkosyl activated activity of enzyme for
oxidation of catechol and pyrogallol, although has inhibitory effect in higher
concentrations. Other ionic, Nonionic detergents and Chaotropic agents showed
inhibitory effect on activity of PPO in soluble and in partial purified fraction.
Inhibitory effect of Urea, GnHcl, NP-40, Triton x-100 and Sodium cholate in
presence of catechol is more than these effect in presence of pyrogallol. On the
other hand, sodim cholate and NP-40 has more inhibitory effect on PPO activity in
presence of pyrogallol at high concentrations. The same effects were obtained on
the partially purified enzyme. Results identified and confirmed the differences in
structure and conformation of enzyme in soluble and in partial purified fraction for
oxidation of different substrates.
