4 replies to this topic

[AnnaSh]

Hello!

I've a question about the mathematical elaboration of kinetic data to establish if a phenomenon of membrane transport can be due to endocytosis. Plotting the initial velocity values against the concentrations of substrate, I obtained a hyperbolic curve, typically associated to a saturable transport. Plotting the velocity values against the log [concentration] I obtained a sigmoid curve. Can this curve be associated to an endocytosis process? Have you any suggestions to opportunely elaborate these data?

Thank you in advance for your replies.

[mdfenko]

hyperbolic curves look sigmoidal when you plot them on semi-log. i don't think you can make any decisions based on that phenomenon.

[AnnaSh]

Thanks for your reply!

I was suspecting it wasn't the right way to show endocytosis. In your opinion can I try another mathematic tool to give an indication for an endocytosis phenomenon? Apart from my studies, does it exist? I hope you can help me!

Thanks!!!

[mdfenko]

i'm not sure that i can help you further. my experience is with enzyme kinetics.

with enzyme kinetics you may use an inverse (lineweaver-burk) plot (1/v vs 1/s). this will give you such information as Vmax and Km.

a hill plot (v/(vmax-v) vs s) plotted on semi-log can help you visualize cooperativity.

Edited by mdfenko, 24 September 2009 - 07:32 AM.

[AnnaSh]

Hi!
I've already used Hill and Eadie-Hofstee plots to gain info about the involvement of one or more transporters and cooperativity.

I think it's time to surrender! For weeks I've been searching for a literature reference solving my question !

Thank you so much anyway!!!