Researchers want to follow where the NMR-active Nitrogen appears in the different urea cycle steps occurring in the liver. Draw structures for the following products and indicate where the label would be located. 3 pts

a) 15N-labeled glutamate is administered. Where does the 15N-label appear on citrulline? b) 15N-labeled aspartate is administered. Where does the 15N-label appear on urea?

c) 15N-labeled glutamine is administered. Where does the 15N-label appear on arginine?