Subunit and chemical composition of citrate lyase from Klebsiella pneumoniae.

Citrate lyase from Klebsiella pneumoniae (previously called Klebsiella aerogenes) is shown by amino acid sequencing techniques to contain equimolar amounts of three nonidentical subunits. Together with the molecular weight of the enzyme, this finding is interpreted to indicate that there are 6 mol of each of these subunits per mol of native enzyme. A partial amino acid sequence of each of the three subunits is presented. The pure enzyme with a specific activity of 73 units/mg of dry protein has an absorbance index (E1% 1 cm at 278 nm) of 6.2. The amino acid composition of the native enzyme is presented. In addition, the amounts of adenine, phosphate, taurine (from cysteamine), and "ribose," present as a bound cofactor of unknown structure, have been estimated. A comparison of amino acid compositions and the partial amino acid sequences of two of the subunits reveals some resemblance between them.