THE HETEROGENEITY OF PANCREATIC DEOXYRIBONUCLEASE

Abstract

The action of crystalline pancreatic deoxyribonuclease on sodium oligonucleotides in the presence of manganous ions has been studied and a pH optimum of 6.6 observed. Inhibition of the enzyme activity by increased ionic strength of the digest occurred. The liberation of products soluble in uranyl acetate – trichloroacetate was found to vary with enzyme concentration and the relative activity of the enzyme on oligonucleotides was best determined by a logarithm-plot method. The activity of the enzyme towards deoxyribonucleic acid or sodium oligonucleotides as substrate was not affected by treatment with acetone. Evidence of heterogeneity in the crystalline enzyme preparation was obtained using paper electrophoresis and chromatography on carboxymethylcellulose. Two fractions were separated that showed different ratios of activity towards the two substrates employed.