The extracellular nuclease activity of Micrococcus sodonensis: III. Kinetic studies and control of production

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Abstract 1. 1. Kinetic analyses of the purified nuclease of Micrococcus sodonensis yielded K m values of 2.9 · 10 −6 and 2.83 · 10 −5 M for RNA and AMP, respectively. 2. 2. AMP was inhibitory to ribonuclease activity and apparent non-competitive kinetics were obtained with a K i of 2.9 · 10 −3 M . 3. 3. Both diesterase and monoesterase activities were stimulated by chelating agents such as glycine, histidine and EDTA, and by sulfhydryl compounds such as mercaptoethanol, cysteine and GSH. p- Chloromercuribenzoate was inhibitory to both activities as were certain of the purine nucleotide analogues such as inosine 5′-chloromethylphosphonate. 4. 4. Studies with metabolite indicated that enzyme synthesis was controlled by the intracellular pyrimidine nucleotide concentration. A cytidine nucleotide is implicated. 5. 5. The data presented in the paper add additional support to the “one protein-two activities” concept for this enzyme.