Physiological regulation of the properties of alcohol dehydrogenase II (ADH II) of Zymomonas mobilis: NADH renders ADH II resistant to cyanide and aeration.
The variable cyanide-sensitivity of the iron-containing alcohol dehydrogenase isoenzyme (ADH II) of the ethanol-producing bacterium Zymomonas mobilis was studied. In aerobically grown permeabilized cells, cyanide caused gradual inhibition of ADH II, which was largely prevented by externally added NADH. Cyanide-sensitivity of ADH II was highest in cells grown under conditions of vigorous aeration, in which intracellular NADH concentration was low. Anaerobically grown bacteria, as well as those cultivated aerobically in the presence of cyanide, maintained higher intracellular NADH levels along with a more cyanide-resistant ADH II. It was demonstrated that cyanide acted as a competitive inhibitor of ADH II, competing with nicotinamide nucleotides. NADH increased both cyanide-resistance and oxygen-resistance of ADH II.
Kalnenieks
Uldis
U
Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda boulv. 4, 1586 Riga, Latvia. kalnen@lanet.lv
Galinina
Nina
N
Toma
Malda M
MM
D000332:Aerobiosis; D000426:Alcohol Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003486:Cyanides / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D009243:NAD / Q000378:metabolism*; D017355:Zymomonas / Q000201:enzymology* / Q000254:growth & development
D003486:Cyanides; D004791:Enzyme Inhibitors; D009243:NAD; D000426:Alcohol Dehydrogenase