Homogeneity of the pyruvate dehydrogenase multienzyme complex from Bacillus stearothermophilus.

The pyruvate dehydrogenase multienzyme complex was purified from Bacillus stearothermophilus by means of six gel-filtration column chromatographies; once on Cellulofine GCL-2000, twice on Sepharose CL-2B, and three times on Sephacryl S-500HR. The molecular size distribution of the complex was examined in detail by gel-filtration chromatography, analytical and sucrose-density ultracentrifugations, and dynamic light scattering. The complex was found to be homogeneous; a dimeric complex was undetectable even with a high concentration of protein (below 6.8 mg/ml).