CK2, or Casein kinase 2, beta polypeptide, is a human gene encoded by CSNK2B. It may also be known as: Casein kinase II subunit beta; CK II beta; Phosvitin; Protein G5aBN; CSK2B; G5A. The encoded protein has an amino acid length of 215 and a mass of 24.9 kDa. Other isoforms may exist. CK2 is a member of the Casein kinase 2 subunit beta family. Homologs of this gene exist in other organisms, including: Frog.