Blackwell Publishing Journal Backfiles 1879-2005
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Process Engineering, Biotechnology, Nutrition Technology
A catalase (I.U.B.184.108.40.206) in papaya was extracted, purified and characterized. The enzyme had a pH optimum of 6.1 and was stable when refrigerated or frozen. The enzyme was inactivated by acidification to pH 3.5. Heat inactivation of papaya catalase was biphasic at 55°C and 60°C, and monophasic at 65°C. Kinetics of both phases were first order. The activation energies for the thermal inactivation of the two phases were 85.9 Kcal/mole and 97.0 Kcal/mole. The apparent molecular weight of the enzyme as determined by gel filtration was 160,000. The unsuitability of papaya catalase as a biochemical indicator for heat inactivation is discussed.
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