BIOC12H3 Lecture Notes - Partial Pressure, Cooperative Binding, Phenylalanine
Document Summary
Bioc12fall2012 lecture week 7: protein functions (chapter 15) Small intracellular protein in vertebrate muscles only in cardiac myocytes and skeletal muscle fibres. The colour of myoglobin usually represents the colour of meat (red or purple) Immunohistochemical localization of myoglobin in differentiated mouse c2c12 myotubes green= myoglobin, red= nucleus contains 153 amino acids (sperm whale myoglobin) first protein wih known x-ray structure. Human myoglobin contains 154 amino acids contains 8 helices: a-f and short inter helices region such as cd, ef and gh. Myoglobin is not essential for muscles under normal conditions (knockout mice are normal) the major function of myoglobin is to facilitate oxygen diffusion in muscles. Heme is a porphyrin derivative conaining 4 pyrrole groups (proline side cian is a pyrrolidine group) Heme occurs in many proteins: myoglobulins, hemoglobulin, neuroglobulin, cytochrome c etc. Oxygenation alters the electronic state of the fe2+-heme complex and causes the colour change.
