Anti-bHLHa40 antibodies are protein reagents that detect specific antigens. The bHLHa40 antigen is another term for the human protein transcription factor 15, encoded by the TCF15 gene. The protein is known to function in the regulation of cell differentiation, among other biological roles. Canonically, it has an amino acid length of 199 residues and a mass of 20.8 kilodaltons. Its subcellular localization is in the nucleus and it is expressed in the testis. Other alias names for bHLHa40 include EC2, EC2, and PARAXIS.