[Partial separation of allelic forms of N-acetyltransferase from the rabbit liver using a new method of enzyme...

A new effective method for purification of rabbit liver N-acetyltransferase to apparent homogeneity has been developed. The method consists in polymin P and ammonium sulfate fractionation, DEAE-Sephacel and Ultragel AcA 44 chromatography and chromatofocusing. In final preparations the enzyme was purified 2500-3000-fold and its specific activity was found to be about 3000-4000 units per mg of protein. During chromatofocusing of enzyme preparations on a middle pressure chromatograph FPLC (Pharmacia, Sweden) a partial separation of acetyltransferase allelic forms from fast and slow-acetylators took place. The supposed allelic acetyltransferase forms differ in some biochemical properties. In particular, the slow acetyltransferase form is much more sensitive towards 0.1 M KCl against the rapid enzyme form. It is assumed that the differences between the catalytic properties of acetyltransferase from rapid and slow acetylators may be explained by differences between their polypeptide primary structures.