BCH210H1 Study Guide - Sigmoid Function, Tetrameric Protein, Protoporphyrin Ix
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BCH210H1 Full Course Notes
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Bch210h lisa zhao 2012 | page 1. Hemoglobin is an o2-transporting protein tetrameric protein. Carries o2 in blood throughout the body. Hb quaternary structure has 4 polypeptide units, each subunit similar to myoglobin. Each hb subunit has a heme prosthetic group. Heme is a disk attached to each hb subunit. Has fe2+ coordinated at centre of protoporphyrin ring. Fe2+ and cu+ have strong o2 affinities. 1 link to his f-8 (his93) in hb subunit. O2 binds bw fe2+ and his e-7 (64) = oxygenation. Heme is buried in a crevice in each subunit to prevent fe2+ oxidation. Fe2+ is rapidly oxidized if heme is by itself in h2o. Co binds tightly to heme = co toxicity. Myoglobin is an o2 carrier inside muscle. Monomeric protein, no quaternary structure supplies o2 to tissues in reptiles, birds, and mammals. Mb stays inside the muscle cell (myocyte) Unless you get a heart attack death of muscle cells.
