| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
In a course of studies on biosynthesis of a novel prosthetic group, pyrroloouinoline auinone, a number of methylotrophic bacteria, including obligate and facultatiie strains, which are known to grow on D-fructose but not on D-glucose, were used to see what kinds of enzymes are concerned in biosynthesis of pyrroloquinoline quinone. In spite of a poor enzyme activity of hexokinase and fructokinase, it is interesting to see that the organisms can grow well on D-fructose. After a survey ofenzymes possibly involved in D-fructose metabolism, a fairly strong enzyme activity of ketohexokinase was found in the cell free extract of most of such ibitroorganisms. The enzyme was purified from the cell free extract by a method involving various kinds of chromatography. The enzyme was finally purified to a single protein band with 1,000-fold and 40% yield. Even when examined with a diluted enzyme solution such a level of ug protein per ml, no appreciable inactivation of the enzyme was observed after 30 min heating the enzyme solution at 70ﾟC. A direct examination that the enzyme catalyzes phosphorylation of D-fructose yielding D-fructose-1-phosphate seemed to be quite probable by the following evidence. D-Fructose-6-phosphate was not detected in the reaction mixture because a coupling enzyme system including phosphohexose isomerase and D-glucose-6-phosphate dehydrogenase showed no response to the reaction product, though foreation of ADP was detected by a coupling enzyme system consisting of pyruvate kinase and lactate dehydrogenase.
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