|Budget Amount *help
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1995: ¥4,300,000 (Direct Cost: ¥4,300,000)
The object of this research is the development of stereo-, regio-, and chemoselective biotransformations by the use of a novel enzyme isolated from a microbe. Enzymatic transformations possess several advantages over microbe mediated transformations, e.g., no side reactions catalyzed by other enzymes, etc.
Seven alpha-keto ester reductases (yeast keto ester reductase, YKER-I-VII) were purified from bakers'yeast. Each enzyme reduces alpha-keto esters stereoselectively. Three of them (YKER-I,VI,and VII) can also catalyze the reduction of a beta-keto ester. One of them (YKER-I) catalyzes the reduction of an alpha-diketone giving an alpha-hydroxy ketone. Now, we can prepare chiral hydroxy esters and hydroxy ketones employing a suitable enzyme as a catalyst.
One enzyme that catalyzes the reduction of carbon-carbon double bond in a alpha, beta-unsaturated ketone was purified from bakers'yeast. The reduction of a beta-phenyl enone gives a chiral saturated ketone in excellent stereoselectivity. The enzyme can also catalyze the reduction of carbon-carbon double bond in a nitroolefin giving a chiral nitro compound.
Three beta-keto ester reductases that catalyze the reduction of ethyl 2-methyl-3-oxobutanoate were purified from Geotrichum candidum. One of them affords the anti- (2S,3S) -hydroxy ester selectively, whereas the others give syn- (2R,3S) -hydroxy ester selectively.