Table 4.

Specific activity (mU/mg) of EstA2 and EstB1 on pNP-esters at various temperatures.

Tested substrates (pNP-derivatives)	60°C		70°C		80°C
	EstA2	EstB1	EstA2	EstB1	EstA2	EstB1
2-Methyldecanoate	–	–	–	–	–	0.15 ± 0.04
Ibuprofen	–	1.11 ± 0.31	0.68 ± 0.42	0.63 ± 0.02	2.55 ± 1.89	0.76 ± 0.02
Naproxen	1.01 ± 0.16	1.54 ± 0.03	2.94 ± 0.34	1.29 ± 0.72	3.09 ± 0.07	0.27 ± 0.06
4-Nitrophenyl 6-methyl-2-(ortho-tolyl)hept-5-enoate	–	–	–	–	–	0.63 ± 0.00
Indancarboxylic acid	–	–	–	–	–	–

Activity tests were performed in 850 μL of 50 mM Sørensen buffer containing 0.1% (w/v) gum arabic and 5 mM sodium deoxycholate (pH 8.0 at 60, 70, and 80°C, respectively), mixed with 120 μL of DMSO and 20 μL of 10 mM of the pNP-ester substrates. Within 10 μL residual volume, 0.4 μg of the enzymes were added to the assay, which was performed for 30 min. Absorbance at 400 nm was measured in cuvettes, enzyme-free samples were measured as reference (the molar extinction coefficient was determined as ε = 14,000 M⁻¹ × cm⁻¹).