CA9 (D47G3) Rabbit mAb #5649

Carbonic anhydrases (CA) are a family of ancient zinc metalloenzymes found in almost all living organisms. All CA can be divided into 3 distinct classes (α, β, and γ) that evolved independently and have no significant homology in sequence and overall folding. All functional CA catalyze the reversible hydration of CO₂ into HCO₃^- and H⁺ and contain a zinc atom in the active sites essential for catalysis. There are many isoforms of CA in mammals and they all belong to the α class (1,2).
CA9 is a member of α class and is a plasma membrane protein with the catalytic domain in the extracellular space. Its expression is restricted to very few normal tissues (mainly the gastrointestinal tract) (2). CA9 expression is strongly induced by hypoxia and down-regulated by the wildtype von Hippel–Lindau (VHL) tumor suppressor protein. CA9 expression is increased in many types of tumors, especially solid hypoxic tumors with a poor responsiveness to the conventional radio- and/or chemo-therapies; CA9 is considered to be a tumor hypoxia marker and a promising target for cancer therapeutic intervention (3-5).