about antibody Extinction Coefficient - (Oct/29/2010 )

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!

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