SCN3B, also known as sodium channel subunit beta-3, is an additional auxiliary subunit of the voltage-sensitive sodium channel that modulates channel gating with distinct kinetics. It was detected in brain, heart, kidney, lung, pancreas and skeletal muscle. It is expressed in adult mammalian skeletal muscle and can functionally couple to the skeletal muscle alpha subunit, SkM1. It associates with neurofascin through their extracellular immunoglobulin-like domain. Recombinant human SCN3B, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.