Table 1.

Purification of AxeA from E. coli BL21 (DE3)/pET24d‐axeA.

Purification step	Protein concentration (mg ml−1)	Total protein (mg)	Specific activity (U mg−1)	Total activity (U)	Purification factor	Yield (%)
Crude extract	17.82	481.2	22.9	10 992	1	100
Heat‐treated crude extract	4.84	106.5	50.4	5 363	2.20	48.8
Source 30 Q pooled fractions	1.33	34.6	76.3	2 638	3.34	24.0
Phenyl Sepharose pooled fractions	0.66	27.7	89.1	2 469	3.90	22.5

The enzyme activities were determined at 50°C in 50 mM phosphate buffer pH 6.5 with p‐nitrophenyl acetate (pNP‐acetate) as the substrate. A slightly higher specific activity of the purified enzyme, i.e. 107 U mg⁻¹, was measured in 20 mM Hepes buffer pH 6.5.