The Root effect is a physiological phenomenon that occurs in fishhemoglobin, named after its discoverer R. W. Root. It is the phenomenon where an increased proton or carbon dioxide concentration (lower pH) lowers hemoglobin's affinity and carrying capacity for oxygen.[1][2] The Root effect is to be distinguished from the Bohr effect where only the affinity to oxygen is reduced. Hemoglobins showing the Root effect show a loss of cooperativity at low pH. This results in the Hb-O2 dissociation curve being shifted downward and not just to the right. At low pH, hemoglobins showing the Root effect don't become fully oxygenated even at oxygen tensions up to 20kPa.[2] This effect allows hemoglobin in fish with swim bladders to unload oxygen into the swim bladder against a high oxygen gradient.[3] The effect is also noted in the choroid rete, the network of blood vessels which carries oxygen to the retina.[3] In the absence of the Root effect, retia will result in the diffusion of some oxygen directly from the arterial blood to the venous blood, making such systems less effective for the concentration of oxygen.[4] It has also been hypothesized that the loss of affinity is used to provide more oxygen to red muscle during acidotic stress.[5]
References
^Ito N.; Komiyama N. H.; Fermi G. (1995). "Structure of Deoxyhaemoglobin of the Antarctic Fish Pagothenia bernachii with an Analysis of the Structural Basis of the Root Effect by Comparison of the Liganded and Unliganded Haemoglobin Structures". Journal of Molecular Biology. 250 (5): 648–658. doi:10.1006/jmbi.1995.0405. PMID 7623382.
^ abPelster B (December 2001). "The generation of hyperbaric oxygen tensions in fish". News Physiol. Sci. 16 (6): 287–91. doi:10.1152/physiologyonline.2001.16.6.287. PMID 11719607.
^ abVerde, C., A. Vergara, D. Giordano, L. Mazzarella, and G. di Prisco. 2007. The Root effect - a structural and evolutionary perspective. Antarctic Science 19:271-278.
^Berenbrink M, Koldkjaer P, Kepp O, Cossins AR (March 2005). "Evolution of oxygen secretion in fishes and the emergence of a complex physiological system". Science. 307 (5716): 1752–7. doi:10.1126/science.1107793. PMID 15774753. S2CID 36391252.
^Rummer JL, McKenzie DJ, Innocenti A, Supuran CT, Brauner CJ (June 2013). "Root Effect Hemoglobin May Have Evolved to Enhance General Tissue Oxygen Delivery" (PDF). Science. 340 (6138): 1327–9. doi:10.1126/science.1233692. hdl:2158/1022682. PMID 23766325. S2CID 43241955.
February 01, 2023
root, effect, physiological, phenomenon, that, occurs, fish, hemoglobin, named, after, discoverer, root, phenomenon, where, increased, proton, carbon, dioxide, concentration, lower, lowers, hemoglobin, affinity, carrying, capacity, oxygen, distinguished, from,. The Root effect is a physiological phenomenon that occurs in fish hemoglobin named after its discoverer R W Root It is the phenomenon where an increased proton or carbon dioxide concentration lower pH lowers hemoglobin s affinity and carrying capacity for oxygen 1 2 The Root effect is to be distinguished from the Bohr effect where only the affinity to oxygen is reduced Hemoglobins showing the Root effect show a loss of cooperativity at low pH This results in the Hb O2 dissociation curve being shifted downward and not just to the right At low pH hemoglobins showing the Root effect don t become fully oxygenated even at oxygen tensions up to 20kPa 2 This effect allows hemoglobin in fish with swim bladders to unload oxygen into the swim bladder against a high oxygen gradient 3 The effect is also noted in the choroid rete the network of blood vessels which carries oxygen to the retina 3 In the absence of the Root effect retia will result in the diffusion of some oxygen directly from the arterial blood to the venous blood making such systems less effective for the concentration of oxygen 4 It has also been hypothesized that the loss of affinity is used to provide more oxygen to red muscle during acidotic stress 5 References Edit Ito N Komiyama N H Fermi G 1995 Structure of Deoxyhaemoglobin of the Antarctic Fish Pagothenia bernachii with an Analysis of the Structural Basis of the Root Effect by Comparison of the Liganded and Unliganded Haemoglobin Structures Journal of Molecular Biology 250 5 648 658 doi 10 1006 jmbi 1995 0405 PMID 7623382 a b Pelster B December 2001 The generation of hyperbaric oxygen tensions in fish News Physiol Sci 16 6 287 91 doi 10 1152 physiologyonline 2001 16 6 287 PMID 11719607 a b Verde C A Vergara D Giordano L Mazzarella and G di Prisco 2007 The Root effect a structural and evolutionary perspective Antarctic Science 19 271 278 Berenbrink M Koldkjaer P Kepp O Cossins AR March 2005 Evolution of oxygen secretion in fishes and the emergence of a complex physiological system Science 307 5716 1752 7 doi 10 1126 science 1107793 PMID 15774753 S2CID 36391252 Rummer JL McKenzie DJ Innocenti A Supuran CT Brauner CJ June 2013 Root Effect Hemoglobin May Have Evolved to Enhance General Tissue Oxygen Delivery PDF Science 340 6138 1327 9 doi 10 1126 science 1233692 hdl 2158 1022682 PMID 23766325 S2CID 43241955 Retrieved from https en wikipedia org w index php title Root effect amp oldid 1059542348, wikipedia, wiki, book, books, library,
