Suzanne,
The only non-specific cleavage I have observed with Wako Lys-c is
at the C-terminal side of Cysteine. We have observed this three times in
our lab over several years. The origional WAKO literature states that
cleavage can occur at S-aminoethyl cysteine (the amino rather than amide
form of the acrylamide derivative), which has a very similar structure to
lysine, and cleaves as readily as lysine.
Another alternative is that the WAKO lys-c may be contaminated with
another protease such as chymotrypsin or trypsin.
I'm unsure of why the non-specific cleavage site is a question
since the L/K question is in the middle of the peptide. Was the L observed
at cycle #12 or Cycle #1?
Hope this helps.
Joe
>Has anyone experienced Wako endo LYS-C cutting at amino acid residues other
>than Lysine (K)? I have a client who is perplexed by my results and swears
>there is a Lysine in the position I called a Leucine ( I stand by my
>call). The endo LYS-C generated peptide sequence is as follows
>(K) IGSQYDNYATC*L*AEHSLTEDDIFSIG...
>
>Any experiences with this would be helpful.
Joseph Fernandez
Associate Director
The Rockefeller University
Protein/DNA Technology Center
1230 York Ave. New York, NY 10021
Phone: (212)-327-8869
FAX : (212)-327-8620
email: fernaj@rockvax.rockefeller.edu
Lab Web Page: http://pdtc.rockefeller.edu
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