Date: Fri, 17 Jan 1997 17:09:55 -0800 (PST)
From: Ken Walsh <walsh@u.washington.edu>
Subject: Re: MS/MS of phosphorylated peptide
In-Reply-To: <7337551217011997/A52866/MAI01A/11B18B372200*@MHS>
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Michael
It is not unusual to suffer neutral loss of H3PO4 during CID of a
phosphopeptide. For example see Resing et al Biochemistry 34, 9477, 1995.
Ken Walsh
Dept Biochemistry
Univ Washington
On Fri, 17 Jan 1997, KNIERMAN MICHAEL D wrote:
> I was wondering if anyone have experience in the analysis of
> phosphorylated peptides by MS/MS. We have a peptide that we believe is
> phosphorylated and performed nanospray positive ion MS/MS on a triple
> quadrapole instrument. We know the mass of the base peptide and the mass
> of this particular fraction was +80 Da. The MS/MS spectra of this fraction
> matched better if a dehydroalanine was substituted for the supposed
> phosphorylated ser residue. I also had a peak in the MS/MS spectra that
> was not assignible to the peptide but was -80 Da from the selected ion for
> MS/MS after charge state correction(+2). However I was not able to see a
> peak at 80 Da. in the MS/MS spectra. Has anyone seen the phosphate group
> behave this way in MS/MS? Could it be a sulfate adduct? Any comments would
> be appreciated.
>
> Michael D. Knierman
> Eli Lilly
> knierman@lilly.com
>
> Disclaimer: Any opinions stated above are my opinion and do not reflect any
> position of Eli Lilly and Co.
>
>