Extended Data Fig. 4: BRP peptide is present in human cerebrospinal fluid and mouse brain.
From: Prohormone cleavage prediction uncovers a non-incretin anti-obesity peptide
a–h, Representative extracted ion chromatogram of the parent +3 ion at m/z = 533.3 (a), the MRM 533.3 to 178.1 y1+ ion transition (b), the MRM 799.5 to 239.1 b2+ ion transition (c), the MRM 533.3 to 239.1 b2+ ion transition (d), the MRM 799.5 to 791.2 z12 + + ion transition (e), the MRM 799.5 to 960.7 z7+ ion transition (f), the MRM 799.5 to 1186.7 z9+ ion transition (g), and the parent +2 ion at m/z = 799.5 (h) in human CSF at 15 min. Blue = synthesized amidated BRP standard. Black = amidated BRP peptide in human CSF. i, Concentration of BRP (533.3 to 239.1 b2+ ion transition) in human CSF. j, MS/MS mirror plot of BRP in human CSF and the synthesized BRP standard. k, LC-MS (MS1 spectra) demonstrating the detection of amidated BRP (+3 ion) in male and female mouse brain at 15 min. Blue = synthesized amidated BRP standard. Grey = BRP peptide in Pc1WT mice. Purple = BRP peptide in Pc1N22D/N222D mice. N = 5 pooled brain samples/group. l, LC-MS (MS2 spectra) demonstrating the detection of amidated BRP (538.6 to 178.1 y1+ ion transition) in male and female mouse brain at 15 min. Blue = synthesized amidated BRP standard. Grey = BRP peptide in Pc1WT mice. Purple = BRP peptide in Pc1N22D/N222D mice. N = 5 pooled brain samples/group. Data are presented as mean +/− S.E.M (i).
