Biosynthesis of allene oxides in Physcomitrella patens

BMC Plant Biology

Table 1 Kinetic properties of PpAOS1 with different hydroperoxy fatty acid substrates

Substrate	K_M [μM]	V_max [μM/min]	k_cat [1/min]	k_cat/K_M [min^-1 M^-1 × 10⁶]
9-HPOD	121 +/− 61	0.98 +/− 0.29	32680	270
9- HPOT(n-3)	39 +/− 14	0.20 +/− 0.03	6706	172
9-HPOT(n-6)	46 +/− 17	2.35 +/− 0.37	156733	3426
13-HPOD	83 +/− 42	0.96 +/− 0.27	31856	384
13-HPOT(n-3)	95 +/− 27	0.90 +/− 0.16	30070	316
13-HPOT(n-6)	107 +/− 57	2.77 +/− 0.88	184500	1731
12-HPETE	7 +/− 2	0.23 +/− 0.02	7657	1176

Kinetic properties were determined by measuring the initial time-dependent substrate consumption at 234 nm at different substrate concentrations typically ranging from 2–100 μM. In some cases the highest substrate concentration applied was 150 μM. For analysis between 20 and 30 data points were fitted to the Michaelis-Menten equation. Note that PpAOS1-concentrations used for incubations with 9- and 13-HPOT(n-6) were different (0.05 nM) from those used for incubations with the other substrates (0.1 nM). K_cat values are corrected to 100% heme occupancy from the ~30% heme content in the enzyme preparation.

ISSN: 1471-2229