title: What is the true enzyme kinetics in the biological system? An investigation of macromolecular crowding effect upon enzyme kinetics of glucose-6-phosphate dehydrogenase.
abstract: Enzyme kinetic parameters for rate equations are vital in metabolic network simulation, a major part of systems biology research efforts. Measurements of Michaelis-Menten kinetic parameters Km and Kcat have been performed for enzymes glucose-6-phosphate dehydrogenase (G6P DH) under crowded conditions using molecular crowding agents bovine serum albumin (BSA) and polyethylene glycol (PEG) of 8000 Da molecular weight. An increase in Kcat was observed at very low concentrations of crowding agent, and also at high crowder concentrations when the experiment was performed at 45 °C with PEG. The observed pattern in Kcat for G6P DH at high crowder concentrations has been explained via modelling using excluded volume theory. An increase in rate was observed at 45 °C for G6P DH versus 30 °C; this has been modelled via the Arrhenius equation.
authors.affiliation: Manchester Centre for Integrative Systems Biology, Faculty of Life Sciences, Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
authors.forename: Matthew G S
authors.initials: MG
authors.lastname: Norris
authors.forename: Naglis
authors.initials: N
authors.lastname: Malys
mesh_terms: D000818:Animals; D002417:Cattle; D005954:Glucosephosphate Dehydrogenase / Q000737:chemistry*; D007700:Kinetics; D011092:Polyethylene Glycols / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D005954:Glucosephosphate Dehydrogenase