Table 1.

Relative Activity of Crude Extracts from Petunia Petals and of Purified BSMTs with a Variety of Substrates

SubstrateCrude
 ExtractsBSMT1BSMT2
Salicylic acid100100100
Benzoic acid22.45 ± 0.2516.34 ± 3.7127.27 ± 5.49
3-Hydroxybenzoic acid1.14 ± 0.090.65 ± 0.141.32 ± 0.20
trans-Cinnamic acid1.00 ± 0.020.41 ± 0.050.69 ± 0.11
p-Coumaric acid0.47 ± 0.010.07 ± 0.040.29 ± 0.12
m-Coumaric acid0.51 ± 0.020.24 ± 0.050.50 ± 0.14
o-Coumaric acid0.48 ± 0.020.14 ± 0.070.25 ± 0.05
Benzyl alcohol0.92 ± 0.030.07 ± 0.020.33 ± 0.14
  • Values are averages of three independent measurements. All substrates were tested at a concentration of 2 mM. The BSMT activity with salicylic acid, set as 100%, was 32.15 ± 0.79 pkat/mg protein for crude extracts, 284.9 ± 4.1 pkat/mg protein for BSMT1, and 243.3 ± 20.4 pkat/mg protein for BSMT2.