CAPSAICIN OXIDATION BY PEROXIDASE FROM CAPSICUM-ANNUUM (VAR ANNUUM) FRUITS

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) oxidation by peroxidase ( EC 1.11.1.7) from Capsicum annuum var. annuum fruits is studied. Capsa icin (Sigma) contains two components which are oxidized indistinctivel y by pepper peroxidase when capsaicin disappearance is monitored by HP LC. Spectrophotometric studies illustrated that capsaicin oxidation by pepper peroxidase showed maximal spectral changes at 262 nm. At this wavelength, epsilon262 = 5.3 x 10(3) M-1 cm-1 was calculated for the o nly absorbent oxidation product. The dependence of the capsaicin oxida tion rate by pepper peroxidase on capsaicin and H2O2 concentrations re veals Michaelis-Menten-type kinetics with inhibition at high substrate concentrations and an acidic optimal pH. From these studies, it can b e concluded that capsaicin is oxidized by pepper peroxidase and that a possible participation of peroxidase in capsaicin metabolism in the p epper fruit should be taken into account.