Table 1. Substrate Specificity of MOMT4 on Different Phenolics
SubstrateSpecific Activity (nmol mg−1 min−1)Km (µM)Vmax (nmol mg−1 min−1)kcat/Km (M−1 s−1)
Coniferyl alcohol66.8 ± 0.7 (100)a192.6 ± 24.5b793.0 ± 3.4b2738.7b
Sinapyl alcohol79.6 ± 0.9 (119)68.1 ± 11.1b407.5 ± 16.5b3999.3b
Coniferaldehyde28.7 ± 0.8 (43)6.4 ± 0.522.0 ± 0.42291.8
Sinapaldehyde14.6 ± 0.5 (22)3.0 ± 0.59.3 ± 0.22099.3
P-coumaryl alcohol5.5 ± 0.1 (8.2)190.3 ± 12.013.7 ± 0.448.0
P-coumaraldehyde1.9 ± 0.0 (2.8)171.0 ± 20.63.8 ± 0.214.6
Caffeyl alcohol1.7 ± 0.0 (2.5)
Ferulic acid3.6 ± 0.0 (5)533.2 ± 32.314.2 ± 0.417.8
Sinapic acid1.8 ± 0.0 (3)503.6 ± 12.220.3 ± 0.226.9
Feruloyl CoANDc
Sinapoyl CoAND
Sinapoyl glucoseND
Sinapoyl malateND
  • The relative activity was measured from the reaction at 30°C for 30 min. Kinetic parameters were obtained from the reactions at 30°C for 10 min. The data represent the mean ± se of two replicates.

  • a Data in parentheses represent relative activity.

  • b Data obtained from radioactive assays.

  • c ND, not detectable; no data shown indicates the kinetics were not tested.