[rleung]

Hi,

I am not sure if people here would know, but my book here says that myoglobin is found both in cardiac muscle and smooth muscle, but I don't see how this can be true.  Isn't myoglobin suppose to be primary in skeletal muscle?  I can understand cardiac muscle, but as for smooth muscle, I am lost as to why myoglobin would be found there.

Ryan

[savoy7]

Unless there's new data out there, myoglobin in found in skeletal and cardiac muscle tissue.  I never heard of it in smooth muscle.

[Equi]

Why shouldn't it be found in smooth muscle as well? After all it ensures oxygen supply.

Just another detail: most fast white skeletal muscles fibres don't need that much oxygen anyway, since they work mostly anaerobic as they only have a few mitochondria.

edit: There are some references in this wikipedia article, which might be worth looking at, if you wanna know the exact details.

[savoy7]

As I stated before, in the early 90S, it was most commonly taught that myoglobin (Mb) was found only in cardiac and skeletal muscle cells.  The skeletal muscle cells were the slow-twitch (red) cells. 

In the Journal of Biological Chemistry, Vol. 273, No. 36, Sept 4, 1998, researchers from UTexas appeared to found Mb in rectum, small intestinal, and arterial smooth muscle.

Whether other studies have collaborated this data, I can't say.

[rleung]

I see.  Thank you so much