"MOTHOLOGY OF KINASE ACTIVITY OF NRII NRII (NtrB) - NRI (NtrC) the system of two elements regulates the transcription of regulating ofnitrogen (ntr) genes in reply to the signals of nitrogen and adequacy of carbon. The protein oftransmitter NRII has both NRI kinase and a phosphorylated-NRI (NRI~P) phosphatase. Thephosphatase activity of NRII is speeded up by the protein of signal transduction of PII, whichbinds to NRII. The studies of this system suggested that the kinase activity of NRII was notregulated while phosphatase activity was regulated, , while these activities were not coordinatelyregulated.. MOTHOLOGY OF KINASE ACTIVITY OF NRII by PII For instance, in several different assays, the kinase activity of NRII seemed to go on notdiminished in the presence of PII, although dephosphorylation express of NRI~P can detectedreadily in similar reaction mixtures. In all experiments, NRII and NRI-N were combined with a coupling system, consisting of pyruvate kinase and the lactate dehydrogenase, which measuredthe production of ADP of ATP . When NRI-N restricted in this system of enzyme, the productionof ADP was restricted by the slow rate of dephosphorylation of NRI-N~P. In these conditions,the rate of generation ADP was augmented on the addition of PII. Since the rate of cleavage fromATP to ADP was augmented by the addition of PII, this result suggested that PII did not inhibitthe kinase activity of NRII. In set of all experiments, the rates of autophosphorylation of NRII inpresence and absence of PII were directly examined and no significant difference was noticed. Since in linked experiments dephosphorylation very - express of NRI~P and NRI-N~P by NRIIcould be noticed on the addition of PII, it was concluded that the kinase activity of NRII wasaffected by PII and that the phosphatase SummaryThe article offer to continue our study of genetics, physiology and biochemistry of NRI-NRIItwo - the system of signal transduction which plays a role mattering in the control of theassimilation of nitrogen in E coli. This system provides a paradigm in the regulations of centralmetabolism by the signs of status of nitrogen and carbon. The job of the article of the systemNRI / NRII also provides a paradigm to understand signal transduction system of two elements.Specific aim of the article include: (1) the Determination of the mechanism of regulations ofNRII kinase and activities phosphatase by Pll and (2) the Determination of the mechanism ofNRI ' autophosphatase ' activity and its control by the complex of NRII and Pll. In both Specificcases, biochemical approaches are used to identify surfaces reacting reciprocally of signallingproteins,"