The reversibility of the SDS-mediated activation of latent peach PPO has be
en studied using cyclodextrins as strip detergent agent. Cyclodextrins prod
uced a combined inhibitory effect on enzymatic activity of latent peach PPO
due to the complexation of detergent and the hydrophobic substrate 4-tert-
butylcatechol (TBC) molecules. To study the reversibility of the activation
process, this combined effect has to be separated. On the one hand, the en
zyme was activated by acid-shocking and the activity was measured in the pr
esence of cyclodextrins, using TBC as substrate. The inhibition curves obta
ined permitted study of the complexation of TBC into cyclodextrins. On the
other hand, the enzyme was activated by SDS and the activity in the presenc
e of cyclodextrins was measured using the highly hydrophilic o-diphenol dop
amine as substrate. In this case, the inhibition curves obtained indicated
the reversibility of the activation process when SDS was trapped by cyclode
xtrins, In addition, the complexation constant between SDS and 2-hydroxypro
pyl-beta-cyclodextrins was calculated by measuring conductivity (K-s = 3500
M-1). (C) 2000 Academic Press.