Figure 9.

Six hundred megahertz COSY NMR spectrum of Ins(1,4,6)P₃ solution in D₂O 21 h after the addition of ZmIPK1 protein. Peaks 1 to 6 correspond to Ins(1,4,6)P₃, while peaks 1′ to 6′ correspond to the product Ins(1,2,4,6)P₄. Multiplets at 3.81, 3.68, and 3.59 ppm are due to glycerol present as an impurity in the protein. The large cross peak at 4.74 ppm in the COSY spectrum is due to the residual water peak. This peak was eliminated using a RECUR-TOCSY pulse sequence in the proton spectra shown as one-dimensional projections.