title: A three-enzyme cascade reaction through positional assembly of enzymes in a polymersome nanoreactor.
abstract: Porous polymersomes based on block copolymers of isocyanopeptides and styrene have been used to anchor enzymes at three different locations, namely, in their lumen (glucose oxidase, GOx), in their bilayer membrane (Candida antarctica lipase B, CalB) and on their surface (horseradish peroxidase, HRP). The surface coupling was achieved by click chemistry between acetylene-functionalised anchors on the surface of the polymersomes and azido functions of HRP, which were introduced by using a direct diazo transfer reaction to lysine residues of the enzyme. To determine the encapsulation and conjugation efficiency of the enzymes, they were decorated with metal-ion labels and analysed by mass spectrometry. This revealed an almost quantitative immobilisation efficiency of HRP on the surface of the polymersomes and a more than statistical incorporation efficiency for CalB in the membrane and for GOx in the aqueous compartment. The enzyme-decorated polymersomes were studied as nanoreactors in which glucose acetate was converted by CalB to glucose, which was oxidised by GOx to gluconolactone in a second step. The hydrogen peroxide produced was used by HRP to oxidise 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to ABTS(.+). Kinetic analysis revealed that the reaction step catalysed by HRP is the fastest in the cascade reaction.
authors.affiliation: Department of Organic Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Stijn F M
authors.initials: SF
authors.lastname: van Dongen
authors.forename: Madhavan
authors.initials: M
authors.lastname: Nallani
authors.forename: Jeroen J L M
authors.initials: JJ
authors.lastname: Cornelissen
authors.forename: Roeland J M
authors.initials: RJ
authors.lastname: Nolte
authors.forename: Jan C M
authors.initials: JC
authors.lastname: van Hest
mesh_terms: D002384:Catalysis; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005656:Fungal Proteins; D005942:Gluconates / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D005949:Glucose Oxidase / Q000138:chemical synthesis / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000138:chemical synthesis / Q000378:metabolism; D007700:Kinetics; D007783:Lactones; D008049:Lipase / Q000138:chemical synthesis / Q000378:metabolism; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D005942:Gluconates; D007783:Lactones; D011108:Polymers; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D008049:Lipase; C431349:lipase B, Candida antarctica; D005947:Glucose; C010730:beta-glucono-1,5-lactone