Table 1. Kinetic properties of At4CL2 variants designed to activate sinapic acid
Coumaric acid Caffeic acid Ferulic acid Sinapic acid
At4CL2 variant Km, μM Vmax, nkat/mg SA, nkat/mg Km, μM Vmax, nkat/mg SA, nkat/mg Km, μM Vmax, nkat/mg SA, nkat/mg Km, μM Vmax, nkat/mg SA nkat/mg
WT 233 ± 15 475 ± 94 249 ± 26 22 ± 5 236 ± 30 199 ± 32 n.d. n.d. 1.8 ± 0.2 n.c. n.c. n.c.
PL (M293P + K320L) 22 ± 8 321 ± 46 276 ± 44 41 ± 8 267 ± 91 218 ± 64 30 ± 7 247 ± 37 210 ± 35 n.c. n.c. n.c.
PL + ΔV355 47 ± 6 187 ± 42 146 ± 28 75 ± 20 111 ± 3 68 ± 21 77 ± 7.9 104 ± 13 79 ± 10 382 ± 72 45 ± 9 22 ± 7
PL + ΔL356 33 ± 3 142 ± 33 119 ± 26 109 ± 39 95 ± 15 60 ± 5 55 ± 1.7 78 ± 8 64 ± 3 168 ± 16 31 ± 2 17 ± 2
PL + ΔV355 + ΔL356 n.c. n.c. n.c. n.c. n.c. n.c. n.c. n.c. n.c. n.c. n.c. n.c.
WT + ΔV355 111 ± 24 41 ± 6 28 ± 2 75 ± 8 80 ± 19 58 ± 14 n.d. n.d. 5 ± 1 n.c. n.c. n.c.
  • SA, specific activity with 200 μM phenolic substrate; n.c., no conversion; n.d., not determinable, enzyme activity too low