Amino acid analysis on polyvinylidene difluoride membranes.

A procedure for the amino acid analysis of proteins electrotransferred to polyvinylidene difluoride (PVDF) membranes is described. The proteins are first separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and then electroblotted onto a PVDF membrane. After staining with Coomassie brilliant blue, the visualized protein bands are excised from the membrane.