The process of introducing a phosphate group on to a protein.

Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an organonitrogen stimulus. An organonitrogen compound is formally a compound containing at least one carbon-nitrogen bond.

The uptake and phosphorylation of specific carbohydrates from the extracellular environment; uptake and phosphorylation are coupled, making the PTS a link between the uptake and metabolism of sugars; phosphoenolpyruvate is the original phosphate donor; phosphoenolpyruvate passes the phosphate via a signal transduction pathway, to enzyme 1 (E1), which in turn passes it on to the histidine protein, HPr; the next step in the system involves sugar-specific membrane-bound complex, enzyme 2 (EII), which transports the sugar into the cell; it includes the sugar permease, which catalyzes the transport reactions; EII is usually divided into three different domains, EIIA, EIIB, and EIIC.