ABSTRAT:5’-Phosphodiesterase is a kind enzyme which can directional hydrolyze the nucleic acid to be 5’-Nucleotides, The nucleic acid is source of the life,.the nucleotide .as nucleic acid the basic composition unit, participates in the metabolism essential matter, 5’-Nucleotides which use widely can intensely increases the fresh ,is kind of very valuable material for food to increases the fresh, also is raw materal of many kinds of medicines. At present, the craft of produces 5 ' -nucleotide from the ribonucleic acid (RNA) is using Penicillium citrinum to produce nuclease P1 .This article mainly about the preliminary research on the pure enzyme preparation process. I use the Penicillium citrinum to produce 5’-Phosphodiesterase enzyme, then the fluid was carried on many pure steps ,then gain comparatively pure enzyme - nuclease P1. After 85 hours fermentation, filtrate the thalli out, obtain the crude fluid of enzyme, purefy in 4 ℃, the process of purification including the first deposit by (NH4)2SO4, the heat treatment, the second partial deposit by (NH4)2SO4, deposit by the acetone, Chromatography on sephadex G – 75, freeze-drying and so on. six links obtain a purer enzyme. each process carries on SDS-PAGE rubber separation way to test the purification effect .According to the results, the methord can use Penicillium citrinum to produce liquid which contain nuclease P1 .In the process of experimants, the step of asepsis , preservation of liquid which contain nuclease P1 and control the contents of acetone are important .
Key word: Penicillium citrinum; 5’-Phosphodiesterase; 5 ' -nucleotide; Enzyme activity; Purification