title: Cooperativity in O2 binding to iron porphyrins.
abstract: The solid-gas O2 binding equilibrium has been studied for for ferrous "picket fence" porphyrinates with sterically hindered axial imidazoles. Such systems show significant cooperativity in their binding of O2: at low O2 pressures a low O2 affinity form exists, and at high O2 pressures a higher O2 affinity form develops. Direct analogies are drawn to the cooperativity shown in O2 binding by hemoglobin. These model systems mimic hemoglobin quantitatively.
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007501:Iron; D007700:Kinetics; D010100:Oxygen; D010108:Oxyhemoglobins; D011166:Porphyrins
chemical_list: D010108:Oxyhemoglobins; D011166:Porphyrins; D007501:Iron; D010100:Oxygen
references.citation: J Mol Biol. 1977 Jan 5;109(1):83-97
references.pmid: 14263
references.citation: Angew Chem Int Ed Engl. 1977 Feb;16(2):117-8
references.pmid: 404935
references.citation: Br Med Bull. 1976 Sep;32(3):195-208
references.pmid: 788828
references.citation: Biochim Biophys Acta. 1976 Apr 14;427(2):520-9
references.pmid: 5128
references.citation: Proc Natl Acad Sci U S A. 1974 Apr;71(4):1326-9
references.pmid: 4524640
references.citation: Biochim Biophys Acta. 1975 Jun 12;392(2):319-27
references.pmid: 165836
references.citation: J Am Chem Soc. 1974 Aug 21;96(17):5593-5
references.pmid: 4854361
references.citation: Biochemistry. 1973 Apr 10;12(8):1491-8
references.pmid: 4699980
references.citation: Biochem Biophys Res Commun. 1975 Dec 1;67(3):864-9
references.pmid: 1201076
references.citation: J Am Chem Soc. 1975 Nov 26;97(24):7185-6
references.pmid: 1184895
references.citation: J Am Chem Soc. 1975 Mar 19;97(6):1427-39
references.pmid: 1133392