Table 1

Quantitation of peptides by their fragments

The peptide at m/z 652.0 (M + 3H)3+ in Fig. 4B was fragmented in the Leu-d0 and Leu-d3 form. Intensities and ratios are listed for a number of fragment ions.

IonPeptide labelm/zIntensityObserved ratio
b2Leu-d0171.112710.0
Leu-d3171.11264
y5Leu-d0568.32439.1
Leu-d3571.32221
y6Leu-d0639.411711.1
Leu-d3642.41297
y10Leu-d01095.61910.8
Leu-d31104.6206