This antibody recognizes a protein of 27kDa, identified as Bcl-X. The mAb shows no cross-reaction with Bcl2 alpha or Bax. Bcl-X has two isoforms, XL (long), a 241 amino acid protein which suppresses cell death, and XS (short), a 178 amino acid protein lacking a 63 amino acid domain which functions as a dominant inhibitor of Bcl2.
