Biotin holocarboxylase synthetase: purification from rat liver cytosol and some properties

The purification of biotin holocarboxylase synthetase (EC 6.3.4.10) from rat liver cytosol to a much higher degree of purity than previously reported, is described. The specific enzymatic activity of the final preparation is increased about 7,000 fold over the starting material. The purified preparation elutes from a gel-filtration column in a volume consistent with a molecular size of 100 kDa and examination by SDS-PAGE reveals one major band of M(r) 50 kDa. This suggests that the native synthetase may exist as a dimer of similar weight subunits.