title: Characterization of Proteus vulgaris K80 lipase immobilized on amine-terminated magnetic microparticles.
abstract: Proteus vulgaris K80 lipase was expressed in Escherichia coli BL21 (DE3) cells and immobilized on amine-terminated magnetic microparticles (Mag-MPs). The immobilization yield and activity retention were 84.15% and 7.87%, respectively. A homology model of lipase K80 was constructed using P. mirabilis lipase as the template. Many lysine residues were located on the protein surface, remote from active sites. The biochemical characteristics of immobilized lipase K80 were compared with the soluble free form of lipase K80. The optimum temperature of K80-Mag-MPs was 60°C, which was 20°C higher than that of the soluble form. K80-Mag-MPs also tended to be more stable than the soluble form at elevated temperatures and a broad range of pH. K80-Mag-MP maintained its stable form at up to 40°C and in a pH range of 5.0- 10.0, whereas soluble K80 maintained its activity up to 35°C and pH 6.0-10.0. K80-Mag-MPs had broader substrate specificity compared with that of soluble K80. K80-Mag-MPs showed about 80% residual relative activity after five recovery trials. These results indicate the potential benefit of K80-Mag-MPs as a biocatalyst in various industries.
authors.affiliation: Division of Biotechnology The Catholic University of Korea, Bucheon 420-743, Republic of Korea.
authors.forename: Agnes
authors.initials: A
authors.lastname: Natalia
authors.forename: Lidya
authors.initials: L
authors.lastname: Kristiani
authors.forename: Hyung Kwoun
authors.initials: HK
authors.lastname: Kim
mesh_terms: D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005822:Genetic Vectors; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008280:Magnetics; D008863:Microspheres; D011513:Proteus mirabilis / Q000201:enzymology / Q000235:genetics; D011514:Proteus vulgaris / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D011994:Recombinant Proteins; D008049:Lipase