Properties of 5′-Phosphodiesterase fromAspergillus niger

Abstract

Among 920 strains of fungi tested only black koji-molds were found to be potent producers of 5′-phosphodiesterase. The enzyme from Aspergillus niger was partially purified from aqueous extract of the culture on wheat bran. The enzyme hydrolyzed 3′-hydroxyl-terminated 3′→5′ and 2′→5′ dinucleotides or 3′→5′ and 2′→5′ dinucleoside monophosphates without specificity toward bases or sugars. The enzyme also hydrolyzed p-nitrophenyl ester of nucleoside 5′-monophosphate, ADP, CDP-choline and UDPG to give nucleoside 5′-monophosphate. The enzyme was actually proved to split 2′→5′ dinucleotides in nuclease P₁ digest of technical grade yeast RNA containing several per cent of 2′-5′ phosphodiester linkages in addition to 3′-5′ linkages.