Pur B, or Purine-rich element binding protein B, is a human gene encoded by PURB. It may also be known as: Transcriptional activator protein Pur-beta; Purine-rich element-binding protein B; PURBETA. The encoded protein has an amino acid length of 312 and a mass of 33.2 kDa. Pur B is a member of the PUR DNA-binding protein family. Homologs of this gene exist in other organisms, including: Mouse, Rat.