Neu H C
J Bacteriol. 1968 May;95(5):1732-7. doi: 10.1128/jb.95.5.1732-1737.1968.
All members of the Enterobacteriaceae possess distinct 5'-nucleotidases and cyclic phosphodiesterases (3'-nucleotidases) that can be differentiated from the acid and alkaline phosphatases and the acid sugar hydrolases. The nucleotidases and cyclic phosphodiesterases of the various Enterobacteriaceae are remarkably similar in properties. All of the 5'-nucleotidases hydrolyze 5'-nucleotides, adenosine triphosphate, and uridine diphosphoglucose. Their pH optimum is from 5.7 to 6.1. The cyclic phosphodiesterases hydrolyze 3'-nucleotides, cyclic phosphonucleotides, bis-(p-nitrophenyl)phosphate, and p-nitrophenylphosphate. Their pH optimum is from 7.2 to 7.8. For both enzymes, cobalt showed optimal metal stimulation. An intracellular protein inhibitor for the 5'-nucleotidase is present in all of the Enterobacteriaceae. No inhibitor of cyclic phosphodiesterase activity exists, although hydrolysis of both cyclic phosphonucleotides and 3'-nucleotides is inhibited by ribonucleic acid. Neither of the enzymes is subject to control by phosphate level or by catabolite repression. Of the other bacteria studied, only Haemophilus and Bacillus subtilis contained significant 3'- or 5'-nucleotidase activity.
肠杆菌科的所有成员都拥有独特的5'-核苷酸酶和环磷酸二酯酶（3'-核苷酸酶），它们可与酸性和碱性磷酸酶以及酸性糖水解酶区分开来。各种肠杆菌科的核苷酸酶和环磷酸二酯酶在性质上非常相似。所有的5'-核苷酸酶都能水解5'-核苷酸、三磷酸腺苷和尿苷二磷酸葡萄糖。它们的最适pH值为5.7至6.1。环磷酸二酯酶能水解3'-核苷酸、环磷酸核苷酸、双（对硝基苯基）磷酸酯和对硝基苯基磷酸酯。它们的最适pH值为7.2至7.8。对于这两种酶来说，钴显示出最佳的金属刺激作用。所有肠杆菌科都存在一种5'-核苷酸酶的细胞内蛋白质抑制剂。虽然环磷酸核苷酸和3'-核苷酸的水解都受到核糖核酸的抑制，但不存在环磷酸二酯酶活性的抑制剂。在研究的其他细菌中，只有嗜血杆菌和枯草芽孢杆菌含有显著的3'-或5'-核苷酸酶活性。
