Biochemical, electrophoretic and immunohistochemical aspects of malate dehydrogenase in truffles (Ascomycotina)

The malate dehydrogenase (MDH; EC 1.1.1.37; L-malate-NAD(+)-oxidoreductase) activities of truffles of the genus Tuber (Tuber melanosporum Vittad., Tub er brumale Vittad., Tuber aestivum Vittad., Tuber magnatum Pico, Tuber rufu m Pico) have been characterized with regard to the K-m and V-max values in the direct and reverse reactions. The isoelectrofocusing has revealed bands showing pi values ranging from pH 5.85 to 7.8. The MDH of T. melanosporum has been partially purified by hydroxyapatite treatment, DEAE-cellulose and Sephadex G-75 columns. With the partially purified T. melanosporum MDH act ivity polyclonal anti-T. melanosporum MDH antibodies have been prepared and used to localize MDH in the mycorrhizae and ascocarps of T. melanosporum. These antibodies inhibit T. melanosporum MDH activity as well as that of T. magnatum but not that of rabbit liver; this supports the specificity of th e MDH antibodies used to localize MDH in truffle tissues. (C) 2000 Federati on of European Microbiological Societies. Published by Elsevier Science B.V . All rights reserved.