Partial purification and characterisation of banana [Musa (AAA Group) 'Gros Michel'] polyphenol oxidase |
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Authors: | Chitsuda Chaisakdanugull,& Chockchai Theerakulkait |
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Affiliation: | Department of Food Technology, Faculty of Biotechnology, Rangsit University, Patumthanee 12000, Thailand; Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand |
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Abstract: | Polyphenol oxidase (PPO) from pulp of banana [Musa (AAA Group) 'Gros Michel'] was extracted and precipitated with 80% saturated ammonium sulphate followed by conventional column chromatography on Sephacryl S-200 HR and fast protein liquid chromatography on Mono Q column. The lyophilised PPO obtained from Sephacryl S-200 HR column was used for characterisation and inhibition studies. The partially purified PPO obtained from the Mono Q column exhibited at least three isoenzymes. The banana PPO had optimum pH for activity at 7 and it was stable around the same pH. Only 48% of initial enzyme activity was lost after heating at 70 °C for 30 min. The enzyme was completely inhibited by 2 m m sodium metabisulphite, 2 m m l -cysteine, 4 m m ascorbic acid, and 100 m m 4-hexylresorcinol. The K m and V max of banana PPO for dopamine were 2.08 m m and 0.124 m m min−1 respectively. |
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Keywords: | Banana browning chromatography enzyme inhibition enzyme kinetics polyphenol oxidase |
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