[Encoded as 4 alternative isoforms by human NOS1 Gene (NOS Family), calcium/calmodulin stimulated homodimeric Nitric Oxide Synthase 1 binds FAD and FMN cofactors, contains a PDZ/DHR and a flavodoxin-like domain, requires BH4 which may stabilize the dimer, and synthesizes nitric oxide messenger from L-arginine. Neuronal NO displays neurotransmitter properties. N-truncated Isoform 3 possesses enzymatic activity. C-truncated isoform 4 is produced by frameshift exon insertion. NOS1 may interact with DLG4 and forms a ternary complex with CAPON and RASD1. NOS1 is localized beneath the sarcolemma in fast-twitch skeletal muscle fibers by associating with the dystrophin glycoprotein complex. The N-terminal PDZ domain of the neuronal NOS1 may participate in protein-protein interaction and target nNos to synaptic membranes. PIN inhibition may prevent NOS1 dimerization. (NCI) ( NCI )] (UMLS (NCI) C0907533) Brain Nitric Oxide Synthase; Constitutive NOS; NC-NOS; Neuronal Nitric Oxide Synthase; Neuronal NOS; Nitric Oxide Synthase 1; NNOS; NOS Type I; NOS1; =Amino Acid, Peptide, or Protein; Enzyme ;