Regulation of glycolysis

I. Regulation

• ATP/ADP ratios are important
• Two roles: energy production and building blocks for biosynthesis

II. Regulated Steps

• Phosphofructokinase: Highly regulated
• Allosteric enzyme:
  • Activated by ADP and AMP
  • Inhibited by ATP and Citrate (from TCA cycle)
• Fructose 2,6 bisphosphate regulation
  • Tandem enzyme: PFK-2, both kinase and phsophotase together
  • Fru 2,6 P potent activator of PFK-1
  • prevents inhibition of citrate/ATP for fatty acid biosynthesis
  • Look at Relative velocity curves for PFK-1
  • Effect of glucagon on PFK-1
• Pyruvate kinase
  • allosteric
  • stimulated by fructose 1,6P
  • inhibited by acetyl-CoA, fatty acids
  • protein kinase inhibits pyruvate kinase
• Glyceraldehyde 3-P dehydrogenase
  • stimulated by NAD+