title: Molecular weight of Escherichia coli beta-galactosidase in concentrated solutions of guanidine hydrochloride.
abstract: The molecular weight of Escherichia coli beta-galactosidase was determined in 6m- and 8m-guanidine hydrochloride by meniscus-depletion sedimentation equilibrium, sedimentation velocity and viscosity. Sedimentation equilibrium revealed heterogeneity with the smallest component having a molecular weight of about 50000. At lower speeds, the apparent weight-average molecular weight is about 80000. By use of a calculation based on an empirical correlation for proteins that are random coils in 6m-guanidine hydrochloride, sedimentation velocity gave a molecular weight of 91000, and the intrinsic viscosity indicated a viscosity-average molecular weight of 84000. Heating in 6m-guanidine hydrochloride lowered the viscosity of beta-galactosidase in a variable manner.
mesh_terms: D002498:Centrifugation; D004926:Escherichia coli / Q000201:enzymology*; D005696:Galactosidases; D006146:Guanidines; D006358:Hot Temperature; D008970:Molecular Weight; D014783:Viscosity
chemical_list: D006146:Guanidines; D005696:Galactosidases