function of tropomyosin?

[Smooth Operater]

---

Members don't see this ad.

The answer key from Barron says Tropomyosin blocks the binding site on actin, preventing myosin cross-bridege attachmnt at low Ca 2+ level.

I though myosin cross bridge with actin at "HIGH Ca2+ level" since that's when myosin is stimulated.

Am I getting something wrong here? Thanks!

 

[aranjuez]

http://en.wikipedia.org/wiki/Tropomyosin

Hope that helps.

aranjuez

 

[_veo_]

The answer key from Barron says Tropomyosin blocks the binding site on actin, preventing myosin cross-bridege attachmnt at low Ca 2+ level.

I though myosin cross bridge with actin at "HIGH Ca2+ level" since that's when myosin is stimulated.

Am I getting something wrong here? Thanks!

tropomyosin forms a complex with another protein which I don't remember the name now.. but when high levels of calcium arrive, calcium binds to this complex, which exposes the actin-myosin binding site. So myosin can bind to it.. is it a good explanation?

 

[fancymylotus]

tropomyosin forms a complex with another protein which I don't remember the name now.. but when high levels of calcium arrive, calcium binds to this complex, which exposes the actin-myosin binding site. So myosin can bind to it.. is it a good explanation?

w/troponin,without calcium,the complex blocks the binding site.

 

[_veo_]

w/troponin,without calcium,the complex blocks the binding site.

yup, troponin! thanks..

 

[joonkimdds]

The answer key from Barron says Tropomyosin blocks the binding site on actin, preventing myosin cross-bridege attachmnt at low Ca 2+ level.

I though myosin cross bridge with actin at "HIGH Ca2+ level" since that's when myosin is stimulated.

Am I getting something wrong here? Thanks!

you are right. it prevents myosin cross at low Ca 2+ level. That's why it doesn't prevent at high Ca 2+ level.

there is nothing wrong about Barron, and there is nothing wrong about what u said.

Therefore...what's the problem ?🙂