Properties and Subunit Composition of the Pig Heart 2-Oxoglutarate Dehydrogenase

The 2-oxoglutarate dehydrogenase, one of the component enzymes of the 2-oxoglutarate dehydrogenase complex, has been highly purified. The enzyme has a sedimentation coefficient (s020,w) of 10.3 S and diffusion coefficient (D020,w) of 3.92 x10-7cm2s-1. The weight average molecular weight was estimated to be about 216,000 from the sedimentation equilibrium data. The content of right-handed α helix in the enzyme molecule was estimated to be about 34% by both optical rotatory dispersion and circular dichroism. The enzyme was found to contain 1 molecule of protein-bound thiamine-PP per mole; some other kinetic and protein chemical properties are also reported.