1. A method is described for partial purification of the total aldolase of rabbit brain by ammonium sulphate precipitation followed by fractionation of the aldolase into five electrophoretically distinct forms. 2. The method allows a laboratory-scale preparation of the five aldolases. 3. With the exception of band 3 the fructose 1,6-diphosphate/fructose 1-phosphate activity ratios of the isolated multiple forms show a continuous increase from isoenzyme 1 to isoenzyme 5; this evidence supports the four-sub-unit model.
