protein phosphorylation status in sample buffer - (May/09/2011 )

will my phosphorylated GST tagged peptide stay phosphorylated if stored in regular denaturing sample buffer overnight before running the gel or is it better to run the gel immediately?

Assuming that it is phosphorylated to begin with--ie, you added phosphatase inhibitors and what not to your lysis buffer--it should be fine to run the next day

in general, it is not recommended to store proteins in sample buffer; but if, it would be useful to store in a phosphate containing buffer which, however, is rarely found in sample buffers