I would say that your conclusion of glycosylation is correct.However,I have
some problem with identification of cycle 16.It is generally accepted that
N-glycosylation of asparagine goes along with Ser/Thr two residues toward
the C-terminus.The major question is this:were your cysteines fully
alkylated?If not,the product of sequencing a cysteine
may not be distinguished from serine,especially after several
residues.So,if the protein was alkylated,and cysteine was conclusively
identified,I will have to say that cysteine could be two residues after the
N-linked oligosaccharide.
It is not easy to get an answer for both the oligosaccharide and the amino
acid.The identification of the sugar moiety,
because,after all the steps,you may have an heterogeneous mess,so that MS
may be hard to identify.
Glyko Inc.(www.glyco.com) is a good supplier of enzymes and other
chemicals.Glyko acquired the biochemical
product business from Oxford GlycoSciences.They have a contact place in the
UK.
You can look at the Web site or e-mail them at:<thelab@glyko.com>.
Fulvio Perini,Ph.D.
986805 Nebraska Med.Cntr.
Omaha,NE 68198-6805
ph:402-559-6184/FAX 402-559-4651
fperini@unmc.edu
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