title: Influence of viscosity of enzymatic reactions studied with glucoamylase of Aspergillus niger.
abstract: Viscosity can be interpreted in terms of transport of momentum and, therefore, it should influence the kinetics of enzyme reactions. A theory, developed by Somogyi and Damjanovich ((1975) J. Theor. Biol. 51, 393--401), is based on this idea. Transport of momentum must always be accompanied by the transport of mass and this second influence of viscosity is a limiting factor for fast reactions in the liquid phase. A third aspect is, that the chemical potentials of the components of viscous solutions are altered. This paper reports experiments concerning the influence of the viscosigens (compounds that increase the viscosity of solvents), alginate, sucrose, and maltose on the kinetic behaviour of glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3). The observed invariance of V and the decrease of Km are explained by the increase of chemical potentials and restriction of momentum transport.
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology*; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism*; D005959:Glucosidases / Q000378:metabolism*; D007700:Kinetics; D008320:Maltose; D008433:Mathematics; D013395:Sucrose; D014783:Viscosity
chemical_list: D013395:Sucrose; D008320:Maltose; D005959:Glucosidases; D005087:Glucan 1,4-alpha-Glucosidase