2. Free fatty acids → three fatty acids

Tip

When lack of glucose, the body need new ways to generate acetyl-CoA, which then can be used in TCA cycle

• Fatty acid oxidation
• ketone body metabolism: Ketone bodies are synthesized in liver, then transported in blood to other organs for ketogenolysis, to acetyl-CoA

Regulation by fructose-2,6-bisphosphate

Main idea: Insulin & glucagon control PFK-2 & FBPase-2 → control amount of F-2,6-BP → direction towards gluconeogenesis or glycosis. Fructose bisphosphatase-2 (FBPase-2) and phosphofructokinase-2 (PFK-2) are the same bifunctional enzyme whose function is reversed by phosphorylation by protein kinase A.

• Fasting state: ↑ glucagon → ↑ cAMP → ↑ protein kinase A → ↑ FBPase-2, ↓ PFK-2, less glycolysis, more gluconeogenesis.
• Fed state: ↑ insulin → ↓ cAMP → ↓ protein kinase A → ↓ FBPase-2, ↑ PFK-2, more glycolysis, less gluconeogenesis.

Mnemonic

FaBian the Peasant (FBP) has to work hard when starving. Prince FrederricK (PFK) works only when fed.