Purification of Rabbit Liver Guanine Aminohydroiase

Abstract

Rabbit liver guanine aminohydrolase has been purified 1250-fold by utilization of an affinity chromatographic separation on 9-(p-aminoethoxyphenyl)guanine-Sepharose with 50% recovery of activity. Polyacrylamide gel electrophoresis of the purified preparations revealed several protein bands which corresponded to regions of enzyme activity measured on gels which had been run under the same conditions. Gel concentration studies of the protein migration rate showed that the protein bands differed in molecular size. The minimum molecular weight was 100, 000 from gel permeation chromatography studies. The pH optimum was near pH 8 and the Km, with guanine as substrate was 5.6 × 10^?6M. The latter values are in close agreement with partially purified preparations described in the literature.