Chlorogenate hydrolase-catalyzed synthesis of hydroxycinnamic acid ester derivatives by transesterification, substitution of bromine, and condensation reactions.
A chlorogenate hydrolase (EC 3.1.1.42) synthesized 2-phenylethyl caffeate (2-CAPE) from 5-chlorogenic acid (5-CQA) and 2-phenylethyl alcohol (2-PA) (by transesterification), from 5-CQA and 2-phenylethyl bromide (2-PBr) (by substitution of bromine), and from caffeic acid (CA) and 2-PA or 2-PBr (by condensation) as well as hydrolysis of 5-CQA. Some reaction conditions including pH, temperature, substrate and solvent concentrates, and reaction time were optimized for the production of 2-CAPE. A maximal molar yield of 50% was achieved by transesterification, 4.7% by substitution of bromine, and 13% by condensation. Among the parameters studied for optimization, the pH of the buffer solution and concentration of 2-PA or 2-PBr affected the production of 2-CAPE. The optimum pH for the hydrolysis reaction was within the neutral range (pH 6.5), whereas the residual three reactions were only catalyzed within the acidic range (pH 3.0-4.0). The optimum concentrations of 2-PA and 2-PBr for three reactions were 5-70 vol% and no 2-CAPE was produced in the 2-PA or 2-PBr solutions containing powdered enzyme. The enzyme may bind to the caffeoyl moiety of 5-CQA or CA to form an enzyme-substrate complex. It then catalyzes four different reactions corresponding to the reaction conditions.
Kishimoto
N
N
Graduate School of Applied Life Chemistry, Kinki University, Nara-City, Nara 631-8505, Japan. kisimoto@nara.kindai.ac.jp
Kakino
Y
Y
Iwai
K
K
Fujita
T
T
D001230:Aspergillus / Q000201:enzymology; D001966:Bromine; D002109:Caffeic Acids / Q000737:chemistry / Q000378:metabolism; D002726:Chlorogenic Acid / Q000737:chemistry* / Q000378:metabolism; D003373:Coumaric Acids / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D004951:Esterification; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D015946:Ethylene Dibromide / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000737:chemistry* / Q000378:metabolism; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism
D002109:Caffeic Acids; D003373:Coumaric Acids; D004952:Esters; D015946:Ethylene Dibromide; D002726:Chlorogenic Acid; D006867:Hydrolases; C055494:caffeic acid phenethyl ester; D010626:Phenylethyl Alcohol; D001966:Bromine