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Ethanol cycle in an ethanologenic bacterium
Author(s) -
Kalnenieks U,
Galini,
Toma M.M,
Marjutina U
Publication year - 2002
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/s0014-5793(02)02923-x
Subject(s) - zymomonas mobilis , acetaldehyde , alcohol dehydrogenase , chemistry , biochemistry , ethanol , respiratory chain , glycolysis , nad+ kinase , catalytic cycle , oxidizing agent , bacteria , alcohol , enzyme , ethanol fuel , biology , organic chemistry , genetics
A novel redox cycle is suggested, performing interconversion between acetaldehyde and ethanol in aerobically growing ethanologenic bacterium Zymomonas mobilis . It is formed by the two alcohol dehydrogenase (ADH) isoenzymes simultaneously catalyzing opposite reactions. ADH I is catalyzing acetaldehyde reduction. The local reactant ratio at its active site probably is shifted towards ethanol synthesis due to direct channeling of NADH from glycolysis. ADH II is oxidizing ethanol. The net result of the cycle operation is NADH shuttling from glycolysis to the membrane respiratory chain, and ensuring flexible distribution of reducing equivalents between the ADH reaction and respiration.