CHEM237 Chapter Notes - Chapter 7: Sickle-Cell Disease, X-Ray Crystallography, Fetus

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Chapter 7: oxygen binding to myoglobin and hemoglobin. Myoglobin is a small protein with simple oxygen binding behaviour: found through x-ray crystallography, members of 8 alpha helices, contains a heme group inside hydrophobic pocket between e and f helices. O2 binds to his e7 through hydrogen bonds. When exposed to oxygen, fe(ii) atom becomes oxidized into. Fe(iii), something that cannot bind to o2 and causes the reversibility. Sometimes this causes it to form metmyoglobin and metheglobin, something found in old meat and ried blood. Can also bind to co, no, h2s and have higher affinity than o2, which is why they"re toxic: myoglobin is used to facilitate oxygen diffusion in muscle. Increases solubility of oxygen in muscle cells as its normally low solubility. More important in aquatic animals: yo2 is the fractional saturation, defined as fraction of o2-binding sites occupied by o2 (ranges from 0 to 1)