The identification of the pterin-binding domain in the nitric oxide synthase's sequence.

Comparative studies of primary sequences of nitric oxide synthase (NOS) and pterin-dependent enzymes has shown that the biopterin-dependent site of NOS is localized between the regions responsible for calmodulin and FMN binding. On the example of NOS from rat brain it was demonstrated that this biopterin-binding site is located in the region 750-769. Pairwise alignment of amino acids sequences of NOS from rat brain and rat xantine dehydrogenase revealed that the two proteins are 39.7% identical.