Electrophoretic analysis of enzymes from tropical plants can be very diffie-ult due to the
presence of high concentrations of phenolics in plant tissues. It is believed that these high tannin levels
may serve to protect plants from the numerous insect predators present in the tropics. Different
methods of extraction of enzymes prior to electrophoresis are suggested. A number of factors which
make plant proteins practically unstable and difficult to work with are also mentioned. The occurrence
of tannins in plants and the reactions of these phenolic compounds with proteins and enzymes
are discussed. Techniques for the extraction of enzymes from tannin-rich plants should involve the
removal of phenolic substrates, the inhibition of O-dlfthenol-oxidase activity or the removal of
quinones formed from oxidation by reducing the quinones back to the O-dlfthenol. Chemicals added
into the extracting medium to overcome the problem of interference by tannins include polymers,
copper chelating agents, thiols, ascorbate, metabisulphite, dithionite and b01!ine serum albumin
