title: A comparative approach to carbonic anhydrase: the work of Thomas H. Maren.
abstract: Thomas H. Maren studied carbonic anhydrase (CA) for half a century, venturing into all aspects of this powerful enzyme from active site chemistry to clinical medicine. He was a keen proponent of comparative physiology to illuminate basic principles of the chemistry and biology of CA and spent 47 summers at the Mt. Desert Island Biological Laboratory (MDIBL) studying many non-mammalian species. Following the venerable strategy of selecting the right creature to explore a particular question, Maren derived important insights into the role of CA in ion transport, acid-base regulation and gas exchange. Using the fact that tissue CAs are expressed variably in different species, and that these animals differ in temperature, acid-base status and metabolic rate, he defined the contributions of un-catalyzed and catalyzed CO(2) reactions in many physiological processes. Often this strategy simplified a problem and offered answers not easily obtainable in mammals. As examples, he verified the primary role of HCO(3)(-) as lead ion in CSF formation in fish and extended this to mammals. Using marine fish whose kidneys have very little CA, he uncovered mechanisms of acid-base transfer independent of CA that help to explain why CA inhibition does not lead to total bicarbonate depletion.
mesh_terms: D000143:Acids / Q000378:metabolism; D000818:Animals; D002256:Carbonic Anhydrases / Q000266:history* / Q000502:physiology; D002555:Cerebrospinal Fluid / Q000378:metabolism; D005399:Fishes / Q000378:metabolism; D049673:History, 20th Century; D007668:Kidney / Q000378:metabolism; D008386:Marine Biology / Q000266:history; D010828:Physiology, Comparative / Q000266:history* / Q000379:methods
chemical_list: D000143:Acids; D002256:Carbonic Anhydrases