can anybody think of reason why an N-terminal cysteine looks like a tryptophane
during N-terminal sequence analysis?
We are expecting a Cys in the first cycle but we see a blank (that would match
the Cys suspicion) or a Trp upon reduction alone or upon reduction & alkylation
(using 4-VP). A Cys residue a little down the sequence comes out as expected as
pyridylethylcysteine residue indicating that the chemical reaction worked fine.
Asking the same question from a different angle: how does an oxidized Trp
behave on the sequencer?
Thanks for all your help, Kristine
Kristine Swiderek
Assoc. Research Director, Biological Structure
ZymoGenetics, Inc.
1201 Eastlake Ave. E
Seattle, WA 98102
Phone: (206)515-4901
Fax: (206)442-6608
e-mail: swiderek@zgi.com