Pre-Electrophoretic Labelling of Proteins with a Coloured Water Soluble Edman Reagent
Sodium dodecyl sulphate polyacrylamide gel electrophoresis (Laemmli 1970) (SDS PAGE) is still the most powerful method of resolving a complex mixture of proteins. However, it is generally used as an analytical rather than a preparative tool. With the advent of PVDF membranes which are stable under the conditions employed by the Edman degradation, it has become common to try and obtain N-terminal sequence data from proteins separated by SDS PAGE followed by electrophoretic transfer to a PVDF membrane (Matsudaira 1987). It is also possible to electroelute proteins out of gel slices for sequencing or enzymic digestion. Alternatively the proteins can be enzymically digested within the gel matrix or directly on the membrane after transfer and the peptides eluted for subsequent HPLC purification (Bauw 1989). Both these procedures require the proteins to be stained after electrophoresis in order to locate their position in the gel or on the membrane. The staining process generally fixes the proteins and leads to significant loss of material.
KeywordsLabel Protein Edman Degradation Cyanogen Bromide Electrophoretic Transfer European Molecular Biology Laboratory
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