Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514

Table 2 Purification of the major NADPH-dependent alcohol dehydrogenase AdhB of Thermoanaerobacter sp. strain X514

Purification step	Total protein [mg]	Specific activity [U mg⁻¹]	Total activity [U]	Yield [%]	Purification [fold]
Cell-free extract	512	2.5	1293	100	1.0
Cytoplasm	449	2.6	1150	89	1.0
Q-Sepharose	337	4.8	1599	123	1.9
(NH₄)₂SO₄ precipitation	268	6.6	1772	137	2.6
Phenyl-Sepharose	86.8	14.8	1284	99	5.8
Superose 6	9.2	13.3	122	9.4	5.2
Blue-Sepharose	2.5	35.2	87.3	6.8	13.8

NADPH-dependent ADH activity was measured in 50 mM Tris buffer (pH 7.5) supplemented with 2 mM DTE and 4 µM as NADPH (0.5 mM)-dependent reduction of acetaldehyde (10 mM) at 340 nm. The decrease in absorption of NADPH was followed at 340 nm. One unit represents one µmol of acetaldehyde reduced per minute

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