Fig. 5.

Global kinetic model for NOS catalysis. The biosynthesis of NO and formation of the enzyme ferric heme–NO complex is limited by k_r. This product complex partitions between an NO-releasing (productive) cycle and an NO-oxidizing (futile) cycle. Enzyme partitioning and NO release are determined by the relative rates of k_r, k_ox, and k_off. NOHA, N^ω-hydroxy-l-arginine. Adapted from ref. 7.