On the molecular weights of the three nonidentical subunits of citrate lyase from Klebsiella aerogenes.

The molecular weights of the three nonidentical subunits of citrate lyase of Klebsiella aerogenes have been determined by three methods: sedimentation equilibrium in 6 M guanidinium chloride, sodium dodecyl sulfate gel electrophoresis, and gel filtration on 6 percent agarose column in 6 M guanidinium chloride. The molecular weights of the subunits, names I, II, and III (or acyl carrier protein) in order of elution from the agarose column, were 54,500, 32,000, and 11,000, respectively. The agarose-guanidine column provided a nearly complete separation of the three subunits. The molecular weight of the native enzyme was found by sedimentation equilibrium to be 520,000 plus or minus 10,000. The uncertainties in the molecular weights of the enzyme and its subunits did not permit a valid postulation of the subunit composition.