Resumo

CASTRO RIVERA, Jhon Alexander; BAQUERO DUARTE, Lucia Estrella  e  NARVAEZ CUENCA, Carlos Eduardo. CATALASE, PEROXIDASE AND POLYPHENOLOXIDASE FROM PITAHAYA AMARILLA FRUITS (Acanthocereus pitajaya). Rev.Colomb.Quim. [online]. 2006, vol.35, n.1, pp.91-100. ISSN 0120-2804.

Catalase (CAT), peroxidase (POD) and polyphenoloxidase (PPO) were extracted from the peel of pitaya amarilla (Acanthocereus pitajaya) and were partially characterized. CAT had maximum activities at pH between 6.8 and 7.5 and at temperatures in the range 30 to 50 °C, its K_M value is 442 mM for H₂O₂.The pH for maximum activity of POD was from 5.0 to 5.5 and its temperatures between 20 and 25 °C; POD had a K_M values of 10.6 mM and 5.1 for guaiacol and H₂O₂, respectively. PPO exhibited its maximum activity at pH 7.0 and at temperatures between 30 and 40 °C; PPO had a K_M value of 5.5 mM for L-DOPA. Our results indicate that both POD and PPO play an important role in the browning of the pitaya amarilla peel; on the other hand, it was observed that CAT and POD must have a complementary role in the H₂O₂ degradation in the cells.

Palavras-chave : Catalase; peroxidase; polyphenoloxidase; kinetic properties; fruits; pitaya amarilla; Acanthocereus pitajaya.

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