Anti-SPEG antibodies are used in the immunodetection of the protein striated muscle enriched protein kinase. In humans, the canonical protein has a reported length of 3267 amino acid residues and a mass of 354.3 kDa. Its subcellular localization is in the nucleus. Up to 4 different isoforms have been reported for this protein. It is notably expressed in many tissues, such as the colon, testis, and bronchus. A member of the CAMK Ser/Thr protein kinase protein family, SPEG is known to be involved with muscle cell differentiation and muscle organ development. Post-translational modifications have been described, including phosphorylation. Synonyms for this target antigen include APEG1, BPEG, CNM5, MYLK6, SPEGalpha, SPEGbeta, striated muscle preferentially expressed protein kinase, and APEG-1. SPEG gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species. Some SPEG antibodies may have been used in research and have associated citations. These antibodies are most commonly used in ELISA experiments, among other applications.