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Properties of tomato fruit ACC synthase

Hu Jiancheng, Hua Xuezeng, Liu Yu, Liang Houguo

Laboratory of Plant Physiology,Lanzhou University.Lanzhou 730000,Gansu；China

Abstract

1-Aminocyclopropane-1-carboxylate (ACC) synthase (EC 4,4,1,14) is the key enzyme regulating ethylene biosynthesis in higher plants. Some properties of ACC synthase purified from wound-induced tomato fruit were examined in this study. The optimum pH of the enzyme reaction was 9.5. ACC synthase activity was stablest at pH 8.0 and no irreversible denaturation occurred when the enzyme was kept at pH 7.5-10 for 24h. Km values of the enzyme at pH 8.0 and pH 9.5 were 23 #mu#mol/L and 40 #mu#mol/L, respectively. Light had inhibitory effect on ACC synthase activity, which might result from sensitized photooxidation with pyridoxal-5^-phosphate as photosensitizer.

Key words: Tomato fruit;ACC synthase;Enzyme properties

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Citing This Article：

Hu Jiancheng, Hua Xuezeng, Liu Yu, Liang Houguo. Properties of tomato fruit ACC synthase. Acta Physiol Sin 1998; 50 (2): (in Chinese with English abstract).