title: Enzyme activity in liquid lipase melts as a step towards solvent-free biology at 150 °C.
abstract: Water molecules play a number of critical roles in enzyme catalysis, including mass transfer of substrates and products, nucleophilicity and proton transfer at the active site, and solvent shell-mediated dynamics for accessing catalytically competent conformations. The pervasiveness of water in enzymolysis therefore raises the question concerning whether biocatalysis can be undertaken in the absence of a protein hydration shell. Lipase-mediated catalysis has been undertaken with reagent-based solvents and lyophilized powders, but there are no examples of molecularly dispersed enzymes that catalyse reactions at sub-solvation levels within solvent-free melts. Here we describe the synthesis, properties and enzyme activity of self-contained reactive biofluids based on solvent-free melts of lipase-polymer surfactant nanoconjugates. Desiccated substrates in liquid (p-nitrophenyl butyrate) or solid (p-nitrophenyl palmitate) form can be mixed or solubilized, respectively, into the enzyme biofluids, and hydrolysed in the solvent-free state. Significantly, the efficiency of product formation increases as the temperature is raised to 150 °C.
authors.affiliation: Centre for Organized Matter Chemistry and Centre for Protolife Research, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
authors.forename: Alex P S
authors.initials: AP
authors.lastname: Brogan
authors.affiliation: Centre for Organized Matter Chemistry and Centre for Protolife Research, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
authors.forename: Kamendra P
authors.initials: KP
authors.lastname: Sharma
authors.affiliation: 1] Centre for Organized Matter Chemistry and Centre for Protolife Research, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK [2] School of Cellular and Molecular Medicine, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
authors.forename: Adam W
authors.initials: AW
authors.lastname: Perriman
authors.affiliation: Centre for Organized Matter Chemistry and Centre for Protolife Research, School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Mann
mesh_terms: D002087:Butyrates / Q000737:chemistry; D002384:Catalysis; D004950:Esterases / Q000737:chemistry; D005612:Freeze Drying; D006868:Hydrolysis; D008049:Lipase / Q000737:chemistry*; D010168:Palmitates / Q000737:chemistry; D017433:Protein Structure, Secondary; D012997:Solvents / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D002087:Butyrates; D010168:Palmitates; D012997:Solvents; D014867:Water; C050015:4-nitrophenyl palmitate; C033592:4-nitrophenyl butyrate; D004950:Esterases; D008049:Lipase