| abstract |
A method for characterising polypeptides, which comprises: (a) treating a sample comprising a population of one or more polypeptides with a cleavage agent which is known to recognise in polypeptide chains a specific amino acid residue or sequence and to cleave at a cleavage site, whereby the population is cleaved to generate peptide fragments; (b) isolating a population of the peptide fragments which bear at one end a reference terminus comprising either only an C-terminus or only an N-terminus and which bear at the other end the cleavage site proximal to the reference terminus; and (c) determining a signature sequence of at least some of the isolated framents, which signature sequence is the sequence of a predetermined number of amino acid residues running from the cleavage site; wherein the signature sequence and the relative position of the cleavage site to the reference terminus characterise the or each polypeptide. |