1 reply to this topic

[Sherry Zhu]

Hello everyone:

I have a question about Extinction Coefficient.

I use the tool on http://www.expasy.ch/ and the software calculate the Extinction Coefficient and absorbance (optical density) ,using the following formula: Absorb(Prot) = E(Prot) / Molecular_weight. The Molecular weight in the formula is deduced from the amimo acid sequence I input. However, my sample is a kind of monoantibody which has two glycosyl-chains, the actual MW is bigger than the deduced MW. The software may forget this modification! Now I am confused and I don't know which MW should be used as Molecular_weight in the formula, the deduced value or the actual one? And I am also doubt if the glycosylation has effect on Extinction Coefficient.

Thank you!

Edited by Sherry Zhu, 29 October 2010 - 07:02 AM.

[sgt4boston]

Read some of the posting under "Antibody Concentration" at the top of the list...it may be of help to you.