Carbonic Anhydrase and Heavy Metals

Carbonic anhydrase (CA; EC 4.2.1.1) is a zinc metalloenzyme catalysing the reversible hydration of CO2 to produce H+ and HCO3−. Its activity is virtually ubiquitous in nature. The fundamental role of this biochemical reaction in diverse biological systems has driven the evolution of several distinct and unrelated families of CAs. Five CA families, referred as ┙-, ┚-, ┛-CA, ├, and ζ-CAs have been identified in animals, plants and bacteria (HewettEmmett and Tashian, 1996; Supuran, 2010). These are the ┙-CAs, present in vertebrates, bacteria, algae and plants; the ┚-CAs, predominantly in bacteria, algae and plants; the ┛CAs, mainly present in archaea and some bacteria; the ├-CAs and ζ-CAs only found in some marine diatoms (Supuran, 2010).