ProtSeq: Trp-derivative

RH01358@rh.dk
Thu, 05 Mar 1998 16:44:00 NFT

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