Deducing a peptide sequence from enzymatic and chemical cleavage.© BrainMass Inc. brainmass.com October 24, 2018, 6:15 pm ad1c9bdddf
GRE subject Question
You have isolated and purified a a small octapeptide protein and want to determine its primary structure. Deduce the sequence from the following experimental results.
A) Complete amino acid analysis, corrected for amino acid hydrolysis loss yielded the following composition (Arg, Glu, Lys, Met, Ser, Thr, Trp, Tyr)
B) Reduction with Dansyl Chloride followed by acid hyrolysis and separation yielded the following dansylated compound.: ...
The solution determines the peptide sequencing from the enzymatic and chemical cleavage.
Peptide Sequencing by Selective Cleavage
I have a peptide sequence with no prolines, 2 positively charged residues at the c-terminal ends of 2 fragments created by trypsin cleavage, but shows no fragments from carboxypeptidases A or B. I thought if a positively charged residue was the c-terminal end of the primary peptide, then I should have seen fragments from carboxypeptidase B, since there is no blocking proline by either the Arg or Lys. I am stumped--what am I missing?View Full Posting Details