Abstract:
1,3,6,8-tetrahydroxynaphtha1ene reductase which isolated from Veritcillium
dahliac brm-l , was purified and partially characterised. The result showed that
optimum pH and temperature of the enzyme were pH 7 and 30"C respectively. The
enzyme was stable upto 40"C, above that temperature enzyme activity slowly
declined and inactivated above 60"C. The probable primary sequence of the Nterminus
of the enzyme was A1a-Lys-J1e-Tye-Asp-Asp-Arg-Leu-Thr-G1y
respectively. Met and Arg are the other option for the first and 4th amino acids
respectively.
1,3dihdroxynaphtha1ene is a new substrate for the enzyme and the substrate
specificity of the enzyme for 1,3,6,8-tetrydroxynaphtha1ene (T4HN), 1,3,8-
trihydroxynaphthalene (T3HN) and 1,3-dihydroxynaphthalene (I ,3-DHN) is as
follows.
T4I-1N>T3HN> 1,3-DHN
Emodin appear to be inhibitor for the enzyme whereas 1,3-dihydoxy-6,8-
dimethoxynaphthalene possibly acts as a competitive inhibitor as well as a weaker
substrate for the enzyme.
