In article <3u62u1$jnu at oban.cc.ic.ac.uk>, Mark Pallen <m.pallen at ic.ac.uk>
says:
>A colleague of mine, Gadi Frankel (gfrankel at molbiol.ox.ac.uk) has asked
>me to post the following request:
>>If you have a protein with two or more cyteines in it, what is the best
>and/or easiest biochemical method for determining which, if any, pair
>or pairs of cysteines is/are linked via a disulphide bridge?
>probably the easiest and quickest would be the following provide the protein/
peptide sequence is known.
subject the pure unreduced protein to a protease digest and then analyse the
fragments by mass spec. eg malditof- ms. this gets around the problem of
having to purify out all the peptide fragments as you would for
microsequencing.
the identity of the bridged peptide should become apparent from an analysis of
all potential disulfided bridged peptides from the parent protein. the likely hood
of any two being even simmilar in mass would be very small.
len bell
sunderland.
