Bradford Protein Assay question

[klhayes]

Ok, this seems like a simple question, but I am getting different answers from different people. when I do a Bradford protein assay, I dilute my samples 1:10. When I get my adjusted average, should I multiply that by 10 BEFORE putting it in the equation from the standard curve or do I plug in the adjusted average and then multiply that answer by 10? The answers are not the same according to my calculator. And is there a place that I can find the answer I get so that I can use it as a reference when someone asks? Thanks for reading!

[danfive]

Protein samples are diluted 1:10 not the standards, therefore you use the standards to calculate the concentration ug/ml or ug/ul of the diluted samples, then you correct for dilution factor by multiplying by ten. The point is not to multiply the Absorbance values, or the standards.

[klhayes]

Originally Posted by danfive

Protein samples are diluted 1:10 not the standards, therefore you use the standards to calculate the concentration ug/ml or ug/ul of the diluted samples, then you correct for dilution factor by multiplying by ten. The point is not to multiply the Absorbance values, or the standards.

I understand that I do not dilute the standards. I want to know if I multiply the absorbances of the samples by 10 before I put them into the equation I get from the standard curve?

[danfive]

Originally Posted by klhayes

I understand that I do not dilute the standards. I want to know if I multiply the absorbances of the samples by 10 before I put them into the equation I get from the standard curve?

No, Do not multiply the Absorbance values, use the avg abs to calculate the protein conc of the dilution then multiply times the dilution factor.