MBB 222 Study Guide - Midterm Guide: Myoglobin, Allosteric Regulation, Cooperative Binding
20 Dec 2018
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Be able to interpret o2 binding curves for myoglobin and hemoglobin; understand how these curves describe the differential affinities of these proteins for o2 and how these affect their oxygen binding states in different tissues. Myoglobin founds in muscles function is oxygen storage. Eight -helices: a, b, c, d, e, f, g, h residues are often numbered within each helix interior residues are non-polar except residue 7 of helix e (his e7) and his f8, which bind the heme group. Exterior residues include both polar and non-polar amino acids. Binds to oxygen via a permanently bound cofactor/ prosthetic group heme. Heme consists of porphyrin and fe2+ ion. O2 binds heme via the fe2+ ion. 1 ml of human blood carries ~ 5x109 red blood cells (rbcs) Each rbc contains ~3x108 hemoglobin molecules therefore, blood can carry ~2. 5 mm o2, more than pure water (~1 mm o2) Hemoglobin (hb) has 4 subunits that are structurally homologous to myoglobin.
