title: Activity and stability of chemically modified Candida antarctica lipase B adsorbed on solid supports.
abstract: The effect of various covalent chemical modifications on the transesterification activity and stability of adsorbed lipase B from Candida antarctica (CALB) was studied in 2-butanone and o-xylene. CALB species modified with either polyethylene glycol 2000 monomethyl ether (MPEG), polyethylene glycol 300 mono-octyl ether (OPEG) or n-octanol (OCT) were used in combination with a hydrophobic (Accurel) and a hydrophilic (Duolite) support. The thermostabilities of adsorbed CALB in both solvents, and that of free CALB in o-xylene were not influenced by the modifications. In contrast, the thermostability of free CALB in 2-butanone decreased 2.5-fold after MPEG modification and increased 1.5-fold after modification with OPEG and n-octanol, compared to that of native CALB. The activities of the native and modified CALB species were up to 9-fold higher after adsorption onto Accurel than those of the corresponding free enzymes. Adsorption of these enzyme species onto Duolite only resulted in a 2- to 3-fold increase in the activity of OPEG- and OCT-modified CALB. The modified CALB species adsorbed onto Accurel show similar or up to 2-fold lower activities than do native adsorbed CALB species, while 1.5- to 6-fold higher activities were found for modified CALB species adsorbed onto Duolite. We propose that hydrophobic modifiers induce conformational changes of CALB during adsorption on a hydrophobic support whereas all three modifiers protect CALB from structural alterations during adsorption onto a hydrophilic support.
authors.affiliation: Department of Enzymology and Protein Engineering, Utrecht University, The Netherlands.
authors.forename: B C
authors.initials: BC
authors.lastname: Koops
authors.forename: E
authors.initials: E
authors.lastname: Papadimou
authors.forename: H M
authors.initials: HM
authors.lastname: Verheij
authors.forename: A J
authors.initials: AJ
authors.lastname: Slotboom
authors.forename: M R
authors.initials: MR
authors.lastname: Egmond
mesh_terms: D000042:Absorption; D002175:Candida / Q000201:enzymology*; D002411:Cation Exchange Resins / Q000378:metabolism; D003911:Dextrans / Q000494:pharmacology; D004800:Enzymes, Immobilized / Q000187:drug effects* / Q000378:metabolism*; D005656:Fungal Proteins / Q000187:drug effects / Q000378:metabolism; D008049:Lipase / Q000187:drug effects* / Q000378:metabolism*; D000442:Octanols / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000378:metabolism / Q000494:pharmacology; D017510:Protein Folding; D013696:Temperature; D013997:Time Factors
chemical_list: D002411:Cation Exchange Resins; D003911:Dextrans; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D000442:Octanols; C092277:dextranox-methyl polyethylene glycol; D011092:Polyethylene Glycols; D008049:Lipase