title: Purification and characterization of a hexanol-degrading enzyme extracted from apple.
abstract: An enzyme having activity toward n-hexanol was purified from apple, and its biochemical characteristics were analyzed. The purification steps consisted of sedimentation with ammonium sulfate, DEAE Sepharose Fast Flow ion exchange chromatography, and Sephadex G-100 column. The obtained enzyme had a yield of 16.00% with a specific activity of 18879.20 U/mg protein and overall purification of 142.77-fold. The enzyme showed activity to isoamylol, 1-propanol, n-hexanol, and isobutanol but not toward methanol and ethanol. With n-hexanol as a substrate, the optimum conditions were pH 4.0 and 30 °C for enzyme activity and pH 3.0-4.0 and temperatures below 40 °C for enzyme stability. The enzyme activity was increased significantly by adding l-cysteine and Fe(2+) at all tested concentrations and slightly by Zn(2+) at a high concentration but decreased by additions of EDTA, Ga(2+), K(+), Mg(2+), sodium dodecyl sulfate (SDS), sodium aluminum sulfate (SAS), dithiothreitol (DTT), and glutathione (GSH). The enzyme activities toward n-hexanol and n-hexanal were increased by NADH but decreased by NAD(+), in contrast to a decrease toward n-hexane by addition of both NAD(+) and NADH.
authors.affiliation: College of Food Science and Engineering, Northwest A & F University, Yangling, Shaanxi Province, 712100, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Junling
authors.initials: J
authors.lastname: Shi
authors.forename: Zhongli
authors.initials: Z
authors.lastname: Pan
mesh_terms: D004795:Enzyme Stability; D004798:Enzymes / Q000302:isolation & purification* / Q000378:metabolism*; D005638:Fruit / Q000201:enzymology*; D000441:Hexanols / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D027845:Malus / Q000201:enzymology*; D008670:Metals / Q000494:pharmacology; D009243:NAD / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004798:Enzymes; D000441:Hexanols; D008670:Metals; D009243:NAD; C036260:1-hexanol