Fig. 2. Typical spectra used for the measurement of the pseudo-first-order
unidirectional rate constant for the forward direction
(Kforward) of the arginine kinase reaction. The spectrum
on the left is a control in which the saturating irradiation is applied at a
frequency offset from the arginine phosphate resonance equivalent to that
between the arginine phosphate and 
-ATP resonances (vertical arrow).
The spectrum on the right demonstrates that, when the -P of ATP is
saturated with radiation, a decrease in the arginine phosphate peak is induced
that is proportional to the rate of transfer of the phosphate from arginine
phosphate to ADP (forward arginine kinase reaction). To measure
Kreverse, the arginine phosphate peak is saturated.
