Air during sample loading

[geok19]

Hi,

when I was applying a cell lysate to a FPLC column, air bubbles were accidently introduced from the bottom. Is there any possibility that the amino acids got modified (e.g. oxidation of cysteins (although 3 mM BME was present in the solution))? The proteins in the lysate were denatured as it contained 6 M guanidine hydrochloride. So I am only concerned about chemical modifications.

Thanks.

[Kneeanderthal]

I don't think you have to worry about amino acids getting modified (unless your wanting too look at reduced/oxidised condition of your protein e.g. DTT for reduced conditions). This has happened to me also, the air might affect binding of your column if it gets stuck.