0000000000162812
AUTHOR
W. Pollmann
Isolation and characterization of a chlorogenic acid esterase from Aspergillus niger.
Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split…
Isolierung und Charakterisierung einer Acetylester-Hydrolase aus Aspergillus rtiger / Isolation and Characterization of an Acetylester-Hydrolase from Aspergillus niger
Abstract The characteristic features of an acetic acid esters hydrolyzing enzyme (acetylesterase, EC 3.1.1.16) are described. The pH- and temperature optimum were 7.0 and 40 °C respectively. The stability of the enzyme regarding different pH- and temperature conditions was investigated. The molecular weight of the acetylesterase could be determined to 160000. A small acetic ester hydrolyzing activity was found too with a molecular weight of about 25000. The activity was not inhibited by addition of di-isopropylphosphorofluoridate (DFP) or physostigmine. The KM-value for glyceryl triacetate was about 90 mM. Concentration of the enzyme was done by ultrafiltration and column-chromatography. Th…