A polypeptide was fragmented using trypsin or staphylococcal protease, and the resultant peptides were sequenced.
                
trypsin fragments:    met-cys-glu-val-lys    gly-ala-asp-ser-thr-arg        val-ala-ser-thr-asp-gly


staphylococcal protease fragments:    ser-thr-arg-val-ala-ser-thr-asp        val-lys-lys-gly-ala-asp


a.  What is the polypeptide primary structure?  (show your work below, if necessary)


                                        

b.  From these data, what can you infer about the cleavage specificity of trypsin and staphylococcal protease?

    trypsin cleaves:                     

    staphylococcal protease cleaves:                     

c.  Would CNBr have been useful in this analysis?  Explain.




d.  Describe (identify) and explain the apparent discrepancy between the two sets of results (what is this “discrepancy” and how did it come about?