If you know the Matthews volume, then you can convert to protein
concentration with:
[protein] (mg/mL) = 1/( V_M (A^3/Da) ) * 1.66e-21 (mg/Da) * 1e24 (A^3/mL)
For example, lysozyme crystals (V_M = 2.0 A^3/Da) contain about 830
mg/ml of protein. Most protein crystals are in this ballpark (because
V_M doesn't have much of a range).
If you want molarity, then you also need to know the molecular weight (MW):
[protein] (mol/L) = [protein] (mg/mL) / MW (g/mol)
Or about 60 mM lysozyme monomers in a crystal.
-James Holton
MAD Scientist
On 12/13/2010 12:07 PM, Teresa De la Mora wrote:
Hi all
I'm looking for a way to calculate the protein concentration in a
single crystal. So what I'm thinking is to use the Matthew's number to
calculate how many molecules inside the crystal, then multiply that
number by Avogadro's number to get moles then divide by volume of
crystal. Is this approach correct?
Thank you for your advice/suggestion
Happy holidays! :)
Teresa
Teresa De la Mora-Rey Ph.D.
Dept. Medicinal Chemistry
University of Minnesota
8-101 Weaver-Densford Hall
308 Harvard St. SE, Minneapolis, MN 55455
Lab phone (612) 626-5226
"If you never did you should. These things are fun and fun is good"
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