Probing biosynthesis of plant polyketides with synthetic N-acetylcysteamine thioesters.
Recombinant chalcone synthase (CHS) from Scutellaria baicalensis accepted cinnamoyl diketide-NAC and cinnamoyl-NAC as a substrate, and carried out sequential condensations with malonyl-CoA to produce 2',4',6'-trihydroxychalcone. Steady-state kinetic analysis revealed that the CHS accepted the diketide-NAC with less efficiency, while cinnamoyl-NAC primed the enzyme reaction almost as efficiently as cinnamoyl-CoA. On the other hand, it was for the first time demonstrated that the diketide-NAC was also a substrate for recombinant polyketide reductase (PKR) from Glycyrrhiza echinata, and converted to the corresponding beta-ketohemithioester. Furthermore, by co-action of the CHS and the PKR, the NAC-thioesters were converted to 6'-deoxychalcone in the presence of NADPH and malonyl-CoA.
Oguro
Satoshi
S
School of Pharmaceutical Sciences, and the 21st Century COE Program, University of Shizuoka, 52-1 Yada, Shizuoka 422-8526, Japan.
Akashi
Tomoyoshi
T
Ayabe
Shin-Ichi
S
Noguchi
Hiroshi
H
Abe
Ikuro
I
D000214:Acyl Coenzyme A / Q000737:chemistry / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002250:Carbon Radioisotopes; D002384:Catalysis; D002599:Chalcone / Q000031:analogs & derivatives* / Q000378:metabolism*; D047188:Chalcones; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D003543:Cysteamine / Q000031:analogs & derivatives* / Q000378:metabolism*; D004952:Esters / Q000737:chemistry / Q000378:metabolism; D006035:Glycyrrhiza / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008316:Malonyl Coenzyme A / Q000737:chemistry / Q000378:metabolism; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*
D000214:Acyl Coenzyme A; D001426:Bacterial Proteins; D002250:Carbon Radioisotopes; D047188:Chalcones; D004952:Esters; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; C058644:4-coumaroyl-coenzyme A; D008316:Malonyl Coenzyme A; D002599:Chalcone; D003543:Cysteamine; C022903:cinnamoyl-coenzyme A; C040920:isoliquiritigenin; D000429:Alcohol Oxidoreductases; C087192:polyketide synthase ketoreductase; D000217:Acyltransferases; C020141:flavanone synthetase