Protein Sequencing

[penz]

Hello everyone, I am new here. I have a question about this Biochemistry: See # 16 on this link (http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.section.556#575 ) and the answer can be found when you click on "answers". When I did it, the sequence came out as (AV)®(SY)®. Under the Trypsin, it said it cuts on the Carboxyl side, so I put R-SY but in the answer its the other way around ...®-(YS)... Can someone explain this? Thank you.

[CharonY]

It cuts at the C-terminus after lysine or arginine (except when proline follows). Remember, the notion is, by convention, from the N- to the C- terminus.

 

So cutting close to the C-terminus would leave the amino acid on the "left" side of the chain.