Substrate Specificity of African Oil Palm Tree Peroxidase

I. Yu. Sakharov^1*, M. K. Vesga Blanco², and I. V. Sakharova¹

¹Department of Chemical Enzymology, School of Chemistry, Lomonosov Moscow State University, Moscow, 119899 Russia; fax: (095) 939-2742; E-mail: sakharov@enz.chem.msu.ru

²School of Chemistry, Industrial University of Santander, Bucaramanga, Colombia

^* To whom correspondence should be addressed.

Received September 20, 2001; Revision received May 15, 2002

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The optimal conditions for catalysis by the peroxidase isolated from leaves of African oil palm tree (AOPTP) have been determined. The pH optimum for oxidation of the majority of substrates studied in the presence of AOPTP is in the interval of 4.5-5.5. A feature of AOPTP is low pH value (3.0) at which the peroxidase shows its maximal activity toward 2,2´-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS). Increasing the buffer concentration changes the AOPTP activity, the degree of the effect depending upon the chemical structure of the substrate. Under optimal conditions of AOPTP catalysis, the values of second order rate constant characterizing efficiency of enzymatic oxidation of substrates have been calculated. It was shown that among 12 peroxidase substrates studied, ABTS and ferulic acid are the best substrates for AOPTP. The results show that substrate specificities of AOPTP and royal palm tree peroxidase are similar, but different from substrate specificity of other plant peroxidases.

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KEY WORDS: peroxidase, palm tree, substrate specificity

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