Are you sure that insulin and glucagon binds to PFK2? They are hormone that binds to their receptors outside of the cell and send a signalling to activate phosphatases e kinases.
Good catch! You're absolutely right, insulin and glucagon do not bind directly to PFK-2. When I have time, I'll upload a new video that shows the full signaling pathway.
phosphorylase kinase (a) and phosphatase (e) kinases same? after all both are activated by cAMP dependent protein kinase (b) so basically for an enzyme(not all) to get activated, it has to be phosphorylated (one of the way is signaling via hormones)?
@@sally_vfx The answer to these questions is no. Covalent modification of enzymes through phosphorylation may increase or decrease the rate of the reaction the enzyme catalyzes depending on the specific effect phosphorylation has on that enzyme. As an example, reciprocal regulation of glycogen synthase and glycogen phosphorylase... Phosphorylation of these enzymes, not just by one kinase, but multiple kinases, functions to activate glycogen phosphorylase while simultaneously inhibiting glycogen synthase. As far as whole body homeostasis, this should make sense. In post absorptive and fasted states when glucagon concentrations rise, there is an increase in activation of the adenylate cyclase -> cAMP -> PKA pathway, leading to phosphorylation of these enzymes by PKA, which also phosphorylates phosphorylase kinase, which phosphorylates glycogen phosphorylase. In your example, PKA phosphorylates and activates phosphorylase kinase and simultaneously inhibits, Not activates protein phosphatase. It would not make sense to simultaneously activate two enzymes with opposing functions, which would lead to futile cycling.
Are you sure that insulin and glucagon binds to PFK2? They are hormone that binds to their receptors outside of the cell and send a signalling to activate phosphatases e kinases.
Good catch! You're absolutely right, insulin and glucagon do not bind directly to PFK-2. When I have time, I'll upload a new video that shows the full signaling pathway.
phosphorylase kinase (a) and phosphatase (e) kinases same?
after all both are activated by cAMP dependent protein kinase (b)
so basically for an enzyme(not all) to get activated, it has to be phosphorylated (one of the way is signaling via hormones)?
My first thought too. But I get the point ! I think insulin activates phosphotases and glucagon PKA
@@sally_vfx The answer to these questions is no. Covalent modification of enzymes through phosphorylation may increase or decrease the rate of the reaction the enzyme catalyzes depending on the specific effect phosphorylation has on that enzyme. As an example, reciprocal regulation of glycogen synthase and glycogen phosphorylase... Phosphorylation of these enzymes, not just by one kinase, but multiple kinases, functions to activate glycogen phosphorylase while simultaneously inhibiting glycogen synthase. As far as whole body homeostasis, this should make sense. In post absorptive and fasted states when glucagon concentrations rise, there is an increase in activation of the adenylate cyclase -> cAMP -> PKA pathway, leading to phosphorylation of these enzymes by PKA, which also phosphorylates phosphorylase kinase, which phosphorylates glycogen phosphorylase.
In your example, PKA phosphorylates and activates phosphorylase kinase and simultaneously inhibits, Not activates protein phosphatase. It would not make sense to simultaneously activate two enzymes with opposing functions, which would lead to futile cycling.
@@lauraslusser8710 I was going to mention this as well. Good catch. I like this video - nice work!
You saved my frickin life this is literally all I needed to have it explained and visualized like this!
What is the great animation! These videos should get thousands of views!
Just the animation I needed. Excellent work to get the synopsis
Awesome video! I really like your visual illustrations of these mechanism.
Lovingly explained for visual learners like myself. Thank you Laura. Perhaps your magnum opus will be an explanation of gluconeogensis? :-)
This is amazing! I'll be checking back for more help with MCAT prep.
Well animated and explained, thank you!
PFK--2 the side piece chyck when wifey PFK-1 busy at work
amazing video, great job!!!
Thank you so much.
Thank you. This is so helpful
why don't books show us explanation this easy!
thank you so much!
Thank u so much it really helpfull👌👍
Thank you so much
Thanks a ton
thank youuu
I love you
I hate chemistry 🧪