Lipids as an energy source

From WikiLectures

The utilization of lipids for energy production takes place in three basic phases:

  1. Lipid mobilization - hydrolysis of TAG to MK and glycerol and their transport blood.
  2. Activation of MK in the cytosol and their transport into the matrix mitochondria.
  3. β-oxidation - breaking down MK into acetyl~CoA, which enters the Krebs cycle, or ketone bodies are formed from it.

Lipid mobilization – lipolysis[edit | edit source]

The mobilization of stored lipids is enzymatically ensured by hormone-sensitive lipase' (HSL). It catalyzes the reaction:

TAG → 3 MK + glycerol

The released fatty acids bind to serum albumin, which transports them to their destination (e.g. the liver). Glycerol is transported freely dissolved in plasma.

Regulation of lipolysis[edit | edit source]

As the name suggests, the enzyme is under strict hormonal control. Its activity is stimulated by the ``phosphorylation of its molecule. Insulin as an anabolic hormone causes its inhibition, counterregulatory hormones (glucagon, catecholamines) or thyroid hormones on the contrary activate it.

Reference[edit | edit source]