Recently, I performed an experiment in which we observed the O2 consumption of yeast (S.cerevisiae) by checking the [O2] in the solution we had, with different poisons and everything was fine, but when it comes to replace glucose with succinate, we observed a neat decrease in O2 consumption (worse than with KCN).

I thought it might be because succinate just shortcut the Krebs cycle and that there are less NADH produced, but the yeast still need ATP, so it doesn't make much sense in the end...

Do anyone has an explanation to it? Because I hardly find anything on my side.