Repost: ProtSeq: Trp-OH-derivative?

RH01358@rh.dk
Mon, 09 Mar 1998 13:59:00 NFT

I posted this last week, but got only one reply, which was helpful, but did
not tell me all. Hence I take the liberty to try again:

Dear all,
In a 9-mer peptide purified as such from biological material I have an
unknown residue, which presumably is a Trp-derivative: on the sequencer
the second-last residue (ABI 494) elutes as two peaks, almost equal in
size, one at the position of Trp and one shortly after Ala, but
baseline separated from it. The calculated molecular mass is 1096 Da
compared to the measured 1112, giving a difference of around 16. The
"Delta Mass" compiled by Ken Mitchelhill names beta hydroxylation of
Trp. Does anyone know how this derivative might elute and if it is
naturally occurring?

Best Regards

Anders H. Johnsen
Department of Clinical Biochemistry
The National University Hospital
KB3014, Rigshospitalet
Blegdamsvej 9
DK-2100 Copenhagen, DENMARK

phone: (+45) 3545 3007
fax: (+45) 3545 4640
e-mail: johnsen@rh.dk