Myoglobins functions

Wittenberg JB, Wittenberg BA. 2003. Myoglobin function reassessed. J Exp Biol 206 2011. 

Cole, R. P. (1982) Myoglobin function In exercising skeletal muscle. Science 216 523-525. 

Wittenberg, J. B. Wittenberg, B. A. (1990). Mechanisms of cytoplasmic hemoglobin and myoglobin function. Annual Review of Biophysics and Biophysical Chemistry, 19,217-41. 

Important novel information has thus been obtained for the specific biological function of those molecules, but disappointingly few general lessons have been learned that are relevant for other membrane-bound proteins with different biological functions. In that respect the situation is similar to the failure of the structure of myoglobin to provide general principles for the construction of soluble protein molecules as described in Chapter 2. 

Special Focus Hemoglobin and Myoglobin— Paradigms of Protein Structure and Function... 

Sequence conservation is, in general, much weaker than structural conservation. There are proteins, which are clearly not related in sequence but are closely related in 3D-stmcture and fold, like heamoglobin and myoglobin, which have similar functions. In many proteins, fold elements like 4-helical bundles are repeated. Classifications of known structural folds of proteins are organized in the SCOP or CATH database see e.g., http //scop.mrc-lmb.cam.ac.uk/scop/. 

FIGURE 9.18 The variation of the extent of saturation of myoglobin (Mb) and hemoglobin (Hbl with the partial pressure of oxygen. The different shapes of the curves account for the different biological functions of the two proteins. 

The myoflbers of muscle are not homogenous but can be categorized into red and white on the basis of ATPase activity ( ). Not only the functional properties but also the composition of the two fiber types varies widely. Red fibers, for example, have considerably more myoglobin and lipid than do white type fibers. 

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