Component of the phosphoenolpyruvate-dependent nitrogen-metabolic phosphotransferase system (nitrogen-metabolic PTS), that seems to be involved in regulating nitrogen metabolism. The phosphoryl group from phosphoenolpyruvate (PEP) is transferred to the phosphoryl carrier protein NPr by enzyme I-Ntr. Phospho-NPr then transfers it to EIIA-Ntr. Could function in the transcriptional regulation of sigma-54 dependent operons in conjunction with the NPr (PtsO) and EIIA-Ntr (PtsN) proteins. Enzyme I of the sugar PTS has been shown in PubMed:7876255 to phosphorylate NPr of the nitrogen-metabolic PTS, though much less efficiently than it does HPr. This process may link carbon and nitrogen assimilation. Belongs to the HPr family.