[metorlona]

Hello,

I need some help: I used for dialysing my proteins tris basic and pbs buffers. But I added in my pbs buffer tris basic and I dialysed my proteins in this mixture. Will this have any effect on the final concentration of proteins?
Thanks in advance!!!!! 

I would be so grateful for any help or advice, I must face my supervisor in a few hours...

[Arkcon]

Possibly, but you really haven't given us enough information.  I don't understand how you expect a dialysis to have a final end concentration.  However, if the pH of the buffer is wrong, you may damage the proteins.

[metorlona]

ok...the ph of the buffer it was at it should be ph=7.4 .After dialyzing i had to measure the OD(280 nm) so i could find my concentration.
I know which is my protein! is there more information needed?

[Babcock_Hall]

I am having a hard time understanding what your question is.  If the volume of solution in the dialysis increases (and it usually does), then the protein will become more dilute.  If this is a problem, it may be possible to reconcentrate the protein with ultrafiltration or related techniques.  Neither phosphate nor Tris absorbs strongly at 280 nm in my experience.  Therefore, I don't see why they would interfere with measuring the concentration of protein, although referencing correctly is important.

[metorlona]

ok..i am so thankful!
look i had to dialyse the same protein in 2 different buffers with the same ph=7.4.
The one was PBS while the second one should be Tris -Basic buffer,both in the same volume.The second buffer instead of prepearing in ddH20 i prepared in PBS buffer.It is like adding tris basic and NaCl in PBS. and i had to measure the OD in both situations.it  was then that i realized what i did...it should be not the same indeed..but in this case how i should trust my results? do i have to do the purification of my protein again...the outcome in these case have been affected?