Mechanism of stimulation of endogenous fermentation in yeast by carbonyl cyanide m-chlorophenylhydrazone.
Addition of the uncoupler and protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) to starved yeast cells starts endogenous alcoholic fermentation lasting about 20 min. Hexose 6-phosphates, fructose 2,6-bisphosphate, and pyruvate accumulate in less than 2 min after addition of CCCP from almost zero concentration to concentrations which correspond to 1/5-1/10 of the steady-state concentrations during fermentation of glucose. CCCP immediately causes a decrease of the intracellular cytosolic pH from 6.9 to 6.4. This change activates adenylate cyclase (Purwin, C., Nicolay, K., Scheffers, W.A., and Holzer, H. (1986) J. Biol. Chem. 261, 8744-8749) and leads to the previously observed transient increase of cyclic AMP. It is shown here that the following enzymes known from in vitro experiments to be activated by cyclic AMP-dependent phosphorylation are activated in the CCCP-treated starved yeast cells in vivo: glycogen phosphorylase, trehalase (pH 7), 6-phosphofructo-2-kinase. The activation of 6-phosphofructo-2-kinase leads to an accumulation of fructose 2,6-bisphosphate, which is known from in vitro experiments to activate 6-phosphofructo-1-kinase and to inhibit fructose-1,6-bisphosphatase. All effects observed in the intact yeast cells fit with the idea that the CCCP-initiated activation of adenylate cyclase leads to a sequence of events which by protein phosphorylation and allosteric effects initiates endogenous alcoholic fermentation.
Noshiro
A
A
Biochemisches Institut der Universität Freiburg, Federal Republic of Germany.
Purwin
C
C
Laux
M
M
Nicolay
K
K
Scheffers
W A
WA
Holzer
H
H
D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009570:Nitriles / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*
D009570:Nitriles; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D000242:Cyclic AMP