CHEM 271 Lecture Notes - Lecture 16: Alpha-Enolase, Thiol, Pasteur Effect

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Role is to provide energy, so main regulator is energy charge. Most important regulatory point is phosphofructokinase (pfk), which is the committed step . Inhibition of pfk in turn leads to inhibition of hexokinase pyruvate kinase. Committed step: the notion that all intermediates before an inhibited step will tend to build up, while all those intermediates after the step will tend to decrease. It is a general rule of metabolic regulation that pathways are regulated at the first committed step. The committed step is the one after which the substrate has only one way to go. Pasteur effect: glycolysis is substantially inhibited under aerobic conditions. The step that it is inhibited at is the phosphofructokinase (pfk) step of fructose-1-phosphate -> fructose-1,6-biphosphate. O2 makes ldh work in reverse -- and fast -- to make pyruvate to be used in the tca cycle.