1.10.3.3 additional information - - 439924 1.10.3.3 additional information - different molecular forms vary in resistance to heat inactivation: tetramer of squash and dimer of cucumber being most resistant 439924 1.10.3.3 additional information - enzyme thermal stability in freshly harvested 4, 6, or 8 weeks old leaves and in leaves of the same ages stored at -80°C and thawed at 25°C, overview. In situ thermal inactivation of AAO in cowpea leaves follows first-order kinetics with an Arrhenius dependence 725176 1.10.3.3 additional information - role of copper in heat stability 439912 1.10.3.3 additional information - the thermal inactivation is irreversible, a first-order reaction mechanism 672768 1.10.3.3 - 40 30 min, stable 439920 1.10.3.3 10 - half-life: 1047 min 672768 1.10.3.3 12 - stable for at least 30 days 439919 1.10.3.3 15 - immobilized enzyme retains full activity for 3 months at pH 5.0-7.0, free enzyme looses 40-70% activity within one day at pH 5.0-7.0 439911 1.10.3.3 40 - 24 h, the enzyme retains 70% of its ascorbate oxidase activity 764908 1.10.3.3 40 - stable for 30 min 439938 1.10.3.3 40 50 conversion of octamer and heavier forms to a dimer 439924 1.10.3.3 50 - stable for 5 min 439930 1.10.3.3 50 80 during thermal treatments for 10 min, AAO in broccoli florets and stalks is stable until around 50°C. A 10 min thermal treatment at 80°C almost completely inactivates AAO. AAO inactivation is irreversible since no increase in activity is observed when extracts of thermal treated broccoli are stored at 4°C for 24 h 712620 1.10.3.3 55 - no loss in activity after 30 min, approx. 55% activity after 30 min at 60°C, approx. 30% activity after 30 min at 65°C 439928 1.10.3.3 60 - free enzyme: 20 min, 90% loss of activity, immobilized enzyme: 10% loss of activity 439911 1.10.3.3 60 - stable for 30 min 439932 1.10.3.3 70 - half-life: 21.2 min 672768 1.10.3.3 80 - - 439890 1.10.3.3 80 - 10 min, complete loss of activity 439896 1.10.3.3 90 - thermal inactivation of AAO follows first-order reaction kinetics. Heating at temperatures above 90°C for short times results in a complete AAO inactivation, resulting in a protective effect of L-ascorbic acid toward enzyme-catalyzed oxidation 725176 1.10.3.3 100 - 1 min, all forms of enzyme inactivated 439924 1.10.3.3 100 - complete inactivation after 1 min 439920