title: Purification, immobilization and characterization of linoleic acid isomerase on modified palygorskite.
abstract: Linoleic acid isomerase from Lactobacillus delbrueckii subsp. bulgaricus 1.1480 was purified by DEAE ion-exchange chromatography and gel filtration chromatography. An overall 5.1% yield and purification of 93-fold were obtained. The molecular weight of the purified protein was ~41 kDa which was analyzed by SDS-PAGE. The purified enzyme was immobilized on palygorskite modified with 3-aminopropyltriethoxysilane. The immobilized enzyme showed an activity of 82 U/g. The optimal temperature and pH for the activity of the free enzyme were 30 °C and pH 6.5, respectively; whereas those for the immobilized enzyme were 35 °C and pH 7.0, respectively. The immobilized enzyme was more stable than the free enzyme at 30-60 °C, and the operational stability result showed that more than 85% of its initial activity was retained after incubation for 3 h. The K (m) and V (max) values of the immobilized enzyme were found to be 0.0619 mmol l(-1) and 0.147 mmol h(-1) mg(-1), respectively. The immobilized enzyme had high operational stability and retained high enzymatic activity after seven cycles of reuse at 37 °C.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing University of Technology, No. 5 Xinmofan Road, Gulou District, Nanjing, 210009, People's Republic of China.
authors.forename: Qinghong
authors.initials: Q
authors.lastname: You
authors.forename: Xiulian
authors.initials: X
authors.lastname: Yin
authors.forename: Xu
authors.initials: X
authors.lastname: Gu
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Li
authors.initials: L
authors.lastname: Sang
mesh_terms: D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D048668:Lactobacillus delbrueckii / Q000201:enzymology; D019787:Linoleic Acid / Q000737:chemistry / Q000302:isolation & purification; D017616:Magnesium Compounds / Q000737:chemistry*; D011437:Propylamines; D012821:Silanes / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry*; D013696:Temperature; D019745:cis-trans-Isomerases / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D004800:Enzymes, Immobilized; D017616:Magnesium Compounds; D011437:Propylamines; D012821:Silanes; D017655:Silicon Compounds; D019787:Linoleic Acid; D019745:cis-trans-Isomerases; C477625:amino-propyl-triethoxysilane; C026325:attapulgite