Extraction and DNA Digestion of 5′-Phosphodiesterase from Malt Root

This study investigated the extraction of 5′-phosphodiesterase from malt root and the degradation of nucleic acids by this enzyme. The extraction used grade precipitation with ammonium sulfate and enzymatic hydrolysis. Samples were assayed using the modified Bradford method and high performance liquid chromatography. The results show that 5′-phosphodiesterase is isolated by grade precipitation with 30% and 80% saturation of ammonium sulfate and can be utilized to degrade deoxyribonucleic acid. The hydrolysate has four kinds of deoxynucleotides: 5′-dCMP, 5′-dTMP, 5′-dAMP, and 5′-dGMP. The optimum reaction temperature is 70°C, and the optimum pH is 5.5-6.0 for the reaction. The percentage of deoxynucleotides indicated by the China Pharmacopoeia (2000 edition) in the product is over 70%. The extraction of 5′-phosphodiesterase from malt root is shown to be possible and economical. Products from the enzymatic hydrolysate of DNA meet the pharmacopoeia.