Extinction Co-efficient of a protein - how d i find out? (Jul/18/2006 )

I need to know the extinction co-efficient of my protein, how do i do it?

Expasy does give me a value, that's for protein in 6M Guanidine Hydrochloride. So,

1. How much would this change on a change in the solution in which my protein is?

2. My protein would be in a buffer with SDS, so should that affect?



And importantly,

3. Is there a way to practically determine the Extinction Co-efficient of a protein?



Please do tell me.. Thank you.

---

First you need to purify a protein
second you need to quantitate it by weight, or a protein assay reaction.
then read OD for this protein sol'n made in specified conc.

---

If you have the sequence of your protein, then you can check it out in the Expasy

---

May be.. but then it'll depend on the protein assay that I use.. say BCA and Bradford have different reactions with my protein and would give different value for my protein, how do i know which one is correct?

By weight meaning?

U mean.. have c, l, A and calculate Extinction co-efficient right?



Thanks!

---