The helix-loop-helix (HLH) proteins are a family of putative transcription factors, some of which have been shown to play an important role in growth and development of a wide variety of tissues and species. NHLH1 may serve as DNA-binding protein and may be involved in the control of cell-type determination, possibly within the developing nervous system. Recombinant human NHLH1 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.