Studies on Distribution of Marine Macro-algae in Europe Which Produce Novel Useful Enzymes and Their Structure-Function

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Little has been done about biochemical studies on marine algae as an undeveloped genetic resource mainly because of technical difficulty. The purpose of this study is to find novel enzymes from marine macro-algae collected in Japan and Europe. Moreover we aimed to elucidate the structure and function of a unique vanadium-dependent haloperoxidase (VHPO) from a marine alga Corallina sp.During the period of this study, we collected marine algae around Tottori, Exeter, U.K., and Amsterdam, the Netherlands, and then determined various enzyme activities of cell-free extracts of the algae. We found an alga with a high phosphatase activity. The enzyme activity showed an optimal pH of about 8, optimal temperature of 60-70℃, and the 60% and 80% stabilities after the incubation at 60℃ for 30 min and at pH 3.5-9.0, respectively. Furthermore, the enzyme showed the substrate specificity toward fructose 1,6-bisphosphate (53%), glucose 6-phosphate (19%), and glyceraldehyde 3-phosphate (16%) as well as p-nitrophenylphosphate (100%).We examined the factors for thermostability and organic solvent tolerance of VHPO of C.pilulifera. As a result, holo-VHPO showed tolerance against tetrahydrofuran and acetonitrile as well as ethanol and acetone, whereas apo-VHPO showed tolerance only against acetone.From the X-ray analyses of VHPO, we found the calcium atoms in the VHPO molecule. The Ca atom and vanadate, the prosthetic group of the enzyme, were found to play an important part of the enzyme stabilities.