title: Cooperativity Has Empirical and Ultimate Levels of Explanation.
abstract: Controversy over the meaning of pharmacological parameters often arises because of a lack of appreciation of different hierarchical levels of analysis. In a recent letter in Trends in Pharmacological Sciences, Zhang and Kavana [1] concluded that my two-state model for allosterism lacks cooperativity, even though Figures 5 and 6 in my review [2] illustrate examples of how the two-state model yields specific cooperativity values. Here, I explain how the two-state model (receptor-state analysis) gives rise to the cooperativity parameter (α) of the allosteric ternary complex model (receptor-population analysis).
authors.affiliation: Department of Pharmacology, School of Medicine, University of California, Irvine, Irvine, CA 92697-4625, USA. Electronic address: fjehlert@uci.edu.
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Ehlert
mesh_terms: D000494:Allosteric Regulation; D001285:Atropine / Q000737:chemistry / Q000378:metabolism; D008390:Markov Chains; D008954:Models, Biological; D011956:Receptors, Cell Surface / Q000819:agonists / Q000737:chemistry* / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000737:chemistry / Q000378:metabolism
chemical_list: D011956:Receptors, Cell Surface; D011976:Receptors, Muscarinic; D001285:Atropine