. 2011 Mar;162(5):1119–1135. doi: 10.1111/j.1476-5381.2010.01117.x

Table 1.

Kinetic values in oxygenation of eicosapentaenoic acid (EPA), eicosapentaenoyl-lysoPC or dieicosapentaenoyl-PC by soybean LOX-1, leucocyte 12/15-LOX and human 15-LOX-2

Enzyme	Substrate	K_m (µM)	V_m (units mg⁻¹)	V_m/K_m (units mg⁻¹·µM⁻¹)
Soybean LOX	1-eicosapentaenoyl-lysoPC	4.5 ± 1.2^a	215.6 ± 24.6^a	49.5 ± 8.2^a
	Eicosapentaenoic acid	10.7 ± 0.8^b	214.1 ± 33.4^a	20.1 ± 1.5^b
	Dieicosapentaenoyl-PC	34 064.1 ± 19 137.1^c	0.06 ± 0.02^b	0.002 ± 0.000^c
Leucocyte 12-LOX	1-eicosapentaenoyl-lysoPC	5.6 ± 0.2^a	22.9 ± 5.0^a	5.0 ± 1.9^a
	Eicosapentaenoic acid	20.4 ± 6.2^b	41.8 ± 3.9^b	2.1 ± 0.5^b
	Dieicosapentaenoyl-PC	62 417.2 ± 508.2^c	0.11 ± 0.07^c	0.001 ± 0.000^c
Human 15-LOX-2	1-eicosapentaenoyl-lysoPC	3.7 ± 1.6^a	47.7 ± 15.6^a	12.8 ± 1.2^a
	Eicosapentaenoic acid	21.9 ± 11.1^b	115.1 ± 8.42^b	5.9 ± 0.61^b
	Dieicosapentaenoyl-PC	44 696.2 ± 106.6^c	0.09 ± 0.03^c	0.002 ± 0.000^c

Soybean LOX-1 (2.5 U·mL⁻¹) was incubated with eicosapentaenoic acid, 1-eicosapentaenoyl-lysoPC or dieicosapentaenoyl-PC at various concentrations in 500 µL of 50 mM borax buffer, pH 9.0 at 25°C. Leucocyte 12/15-LOX (2.5 U·mL⁻¹) was incubated with each substrate in 500 µL of 50 mM phosphate buffer (pH 7.4) containing 5 mM EDTA and 0.03% Tween 20. Human 15-LOX-2 (1 U·mL⁻¹) was incubated with each substrate in 500 µL of 50 mM Tris-HCl buffer (pH 7.2) containing 0.003% Tween 20. One unit of LOX were defined as 1 nmol of oxygenation product formed min^-1. Data are expressed as means ± SEM values of triplicates experiments. Means displayed with letter are not significantly different from each other.