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Respiratory behaviour of a Zymomonas mobilis adhB::kan r mutant supports the hypothesis of two alcohol dehydrogenase isoenzymes catalysing opposite reactions
Author(s) -
Kalnenieks U.,
Galini.,
Toma M.M.,
Pickford J.L.,
Rutkis R.,
Poole R.K.
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.08.034
Subject(s) - zymomonas mobilis , acetaldehyde , alcohol dehydrogenase , ethanol , chemistry , chemostat , biochemistry , alcohol , nad+ kinase , steady state (chemistry) , ethanol fuel , bacteria , biology , enzyme , organic chemistry , genetics
Perturbation of the aerobic steady‐state in a chemostat culture of the ethanol‐producing bacterium Zymomonas mobilis with a small pulse of ethanol causes a burst of ethanol oxidation, although the reactant ratio of the alcohol dehydrogenase (ADH) reaction ([NADH][acetaldehyde][H + ])/([ethanol][NAD + ]) remains above the K eq value. Simultaneous catalysis of ethanol synthesis and oxidation by the two ADH isoenzymes, residing in different redox microenvironments, has been proposed previously. In the present study, this hypothesis is verified by construction of an ADH‐deficient strain and by demonstration that it lacks the oxidative burst in response to perturbation of its aerobic steady‐state with ethanol.