A novel malate dehydrogenase from Ceratonia siliqua L. Seeds with potential biotechnological applications

Muccio C.;Guida V.;Di Petrillo A.;Severino V.;Di Maro A.

2012-01-01

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Abstract

A novel malate dehydrogenase (MDH; EC 3.1.1.1.37), hereafter MDHCs, from Ceratonia siliqua seeds, commonly known as Carob tree, was purified by using ammonium sulphate precipitation, ion exchange chromatography on SteamLine SP and gel-filtration. The molecular mass of the native protein, obtained by analytical gel-filtration, was about 65 kDa, whereas, by using SDS-PAGE analysis, with and without reducing agent, was 34 kDa. The specific activity of purified MDHCs (0.25 mg/ 100 g seeds) was estimated to be 188 U/mg. The optimum activity of the enzyme is at pH 8.5, showing a decrease in the presence of Ca2+, Mg2+ and NaCl. The N-terminal sequence of the first 20 amino acids of MDHCs revealed 95 % identity with malate dehydrogenase from Medicago sativa L. Finally, the enzymatic activity of MDHCs was preserved even after absorption onto a PVDF membrane. To our knowledge, this is the first contribution to the characterization of an enzyme from Carob tree sources. © Springer Science+Business Media, LLC 2012.