Table S1.

Enzyme kinetic parameter estimates for modern-day and ancestral xanthine alkaloid-producing enzymes with selected substrates

Enzyme (+substrate)KM (µM)kcat (1/s)kcat/KM (s−1⋅M−1)
Modern-day enzymes
 TcCS1 (X)95.88.37E-050.87
 TcCS2 (3X)49.19.81E-052.00
 PcCS1 (X)95.381.52E-0315.94
 PcCS2 (3X)6779.33E-041.38
 CsXMT1 (1X)657.66.32E-040.97
 CsXMT1 (3X)1,1442.99E-040.26
 CsXMT1 (X)7598.74E-050.12
Ancestral enzymes
 CsAncXMT2 (X)2,7402.48E-040.09
 CsAncXMT2 P25S (X)1,6903.97E-040.23