Production of 5’-Mononucleotides Using Immobilized 5’-Phosphodiesterase and 5’-AMP Deaminase

The preparations and properties of 5′-phosphodiesterase and 5′-AMP-deaminase immobilized on porous ceramics by covalent binding and the production of 5′mononucleotides from RNA using these immobilized enzymes are described. Comparison tests for the properties of both immobilized and native enzymes were carried out. It was found that the pH optima of these immobilized enzymes were shifted toward the acidic side, and their practically operable pH regions were much more broadened. In such acidic pH regions, these immobilized enzymes also showed more excellent heat stabilities. These special characteristics of the immobilized enzymes were quite satisfactory for eliminating possible microbial contamination during the long-term operation of these immobilized enzyme systems. In continuous-column operations, more than 85% hydrolysis of RNA and complete conversion of 5′-AMP to 5′-IMP were maintained for more than 23 days when a 4% RNA solution was charged as the substrate.