BIOSC 1000 Lecture 13: Lecture 13
12 Apr 2019
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Document Summary
Once glucose reaches this point, it is committed to catabolism: aldolase produces two interconvertable 3 carbon sugars, triose phosphate isomerase catalyzes the reversible conversion of dhap to g3p, only glyceraldehyde 3 phosphate can continue on in glycolysis, glyceraldehyde 3 phosphate dehydrogenase adds inorganic phosphate to make a high energy intermediate. In muscle, regulation of glycolysis occurs at 2 highly exergonic (irreversible) reactions: hexokinase, phosphofructokinase (pfk, pyruvate kinase, hexokinase is allosterically inhibited by glucose 6 phosphate, pfk is a tetramer with allosteric binding sites. Atp is acting as substrate and inhibitor: muscle pfk activity increases when the atp/amp ratio decreases, the catalytic sites are occupied (atp is also substrate) & the allosteric sites are, allosteric sites become occupied too, lowering affinity for f6p, activity goes way down, pyruvate kinase is also allosterically inhibited by atp. Pyruvate: product of glycolysis, anaerobic, convert to lactate or ethanol, aerobic, transported into mitochondria.
