Kinetic Data:
This file relates to data presented in Table 1, Table 3 and Figure 2. 
All relevent experiments have been compiled into a single .xlsx file (kinetic_data.xlsx)which can be opened using Microsoft Excel. 
Data shows absrobance change per unit time.

Mass Spectrometry Data:
These files relate to data presented in Table 2 and SI Figure 1.
Files are presented in original .ms1 files which can be opened with Bruker data analysis software.  

20170915_07_000001.ms1 - ScSPT with L-Serine
20170915_08_000001.ms1 - ScSPT with [3,3-D] L-Serine
20170915_09_000001.ms1 - ScSPT with [2,3,3-D] L-Serine
20170915_10_000001.ms1 - ScSPT with [2-13C] L-Serine
20170915_11_000001.ms1 - ScSPT with [1,2,3-13C, 2-15N] L-Serine

20170915_13_000001.ms1 - SpSPT with L-Serine
20170915_14_000001.ms1 - SpSPT with [3,3-D] L-Serine
20170915_15_000001.ms1 - SpSPT with [2,3,3-D] L-Serine
20170915_16_000001.ms1 - SpSPT with [2-13C] L-Serine
20170915_17_000001.ms1 - SpSPT with [1,2,3-13C, 2-15N] L-Serine