| Abstrakt: |
Rabbit muscle phosphoglucose isomerase was subjected to various dissociation methods to determine the number and the size of its subunits. Gel filtration over a 50,000-fold concentration range (0.0001 to 5 mg ml-1) showed that dissociation does not occur simply as a result of dilution. The following subunit molecular weights were measured in denaturing solvents: 64,400 and 64,000 by ultracentrifugation and polyacrylamide gel electrophoresis, respectively, in the presence of sodium dodecyl sulfate; approximately 60,000 by equilibrium sedimentation in the presence of maleic anhydride; and 65,100 by equilibrium sedimentation in the presence of 6 mguanidine hydrochloride. These values correspond to almost exactly one-half of the molecular weight of 132,000 for the native enzyme (Pon, N. G., Schnackerz, K. D., Blackburn, M. N., Chatterjee, G. C., andNoltmann, E. A. (1970) Biochemistry9, 1506), indicating that rabbit muscle phosphoglucose isomerase is composed of 2 subunits of identical molecular weight. |
