Mm. Sojo et al., Partial purification of a banana polyphenol oxidase using triton X-114 andPEG 8000 for removal of polyphenols, J AGR FOOD, 46(12), 1998, pp. 4924-4930
Banana pulp polyphenol oxidase was partially purified in a latent form usin
g sequential aqueous two-phase systems based on Triton X-114 and PEG 8000/p
hosphate. The purification achieved from a crude extract of banana pulp was
5-fold, with 50% recovery of the activity. The (poly)phenols, including ta
nnins, were also reduced to 6% of the original, avoiding the postpurificati
on tanning of the enzyme and rendering only one enzymatic form in contrast
to the many previously shown for this enzyme in both electrophoretic and is
oelectrofocusing methods. The enzyme was kinetically characterized with its
natural substrate (dopamine) and tert-butylcatechol in the presence and in
the absence of the main activating agent, sodium dodecyl sulfate. In addit
ion, the effect of several inhibitors was also tested, and the K-s, values
of the two most effective substrate analogues (tropolone and kojic acid) we
re determined.