title: Characterization and optimization of carboxylesterase-catalyzed esterification between capric acid and glycerol for the production of 1-monocaprin in reversed micellar system.
abstract: Calotropis procera R. Br. carboxylesterase (EC 3.1.1.1) solubilized in reversed micellar glycerol droplets containing a very small amount of water (less than 5ppm) and stabilized by a surfactant effectively catalyzed the esterification between glycerol and capric acid to produce 1-monocaprin. Reaction variables including surfactant types, organic solvent media, reaction time, G-value ([glycerol]/[capric acid]), R-value ([water]/[surfactant]), pH, temperature, and types of metal ion inhibitors on the carboxylesterase-catalyzed esterification were characterized and optimized to efficiently produce 1-monocaprin. Bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and isooctane were the most effective surfactant and organic solvent medium, respectively, for 1-monocaprin formation in reversed micelles. The optimum G- and R-values were 3.0 and 0.05, respectively, and the optimum pH and temperature were determined to be 10.0 and 60 degrees C, respectively. K(m,app.) and V(max,app.) were calculated from a Hanes-Woolf plot, and the values were 9.64 mM and 2.45 microM/min mg protein, respectively. Among various metal ions, Cu(2+) and Fe(2+) severely inhibited carboxylesterase-catalyzed esterification activity (less than 6.0% of relative activity).
authors.affiliation: Department of Food Science and Technology, Seoul National University of Technology, Seoul 139-743, Republic of Korea.
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Park
authors.forename: Oh Taek
authors.initials: OT
authors.lastname: Kwon
authors.forename: Seon Min
authors.initials: SM
authors.lastname: Ahn
authors.forename: JaeHwan
authors.initials: J
authors.lastname: Lee
authors.forename: Pahn-Shick
authors.initials: PS
authors.lastname: Chang
mesh_terms: D031107:Calotropis / Q000201:enzymology; D043182:Carboxylesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D003652:Decanoic Acids / Q000737:chemistry / Q000378:metabolism; D045703:Emulsifying Agents / Q000737:chemistry / Q000378:metabolism; D004951:Esterification; D005989:Glycerides / Q000737:chemistry / Q000378:metabolism*; D005990:Glycerol / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008823:Micelles; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D003652:Decanoic Acids; D045703:Emulsifying Agents; D005989:Glycerides; D008823:Micelles; D010940:Plant Proteins; C004204:rac-glycerol 1-monodecanoate; D003300:Copper; D007501:Iron; D043182:Carboxylesterase; D005990:Glycerol