However, treatment with urea is known to modify proteins (N-term/Lys/Arg),
which could ultimately effect crystallization.
Is this something that people generally worry about?
For example
-would you bother cleaning up the urea by ion exchange
-get ultra pure urea (ultra $$$)
-change to guanidinium chloride
-hope that it might benefit crystallization (i.e. similar to methylation
of lysines)
Have ~ 50 mM glycine or tris in your urea solution and prepare it fresh.
Then you don't have to worry about carbamylation.
Dima
