Abstract
1. Polynucleotide phosphorylase was purified 200-fold from Halobacterium cutirubrum. 2. It is membrane-associated and can be solubilized by sonication. 3. The purified enzyme requires a high ionic strength for both stability and activity. 4. It is Mn2+-dependent, has all three typical polynucleotide phosphorylase activities and is specific for nucleoside diphosphates. 5. The enzyme is of low molecular weight.