Reciporical Control of Fatty Acid Synthesis and Oxidation

How is Fatty Acid Synthesis and Oxidation controlled? How do they not both occur at the same time?



Rate limiting step in FA Synthesis is the formation of Malonyl CoA by Acetyl-CoA Carboxylase (ACC)

ACC is down-regulated by Palmitoyl-CoA, PKA (Glucagon and Epinepherine), and AMP-Activated Protein Kinase

ACC is up-regulated by Citrate and Protein Phosphatase (insulin)

The breakdown of Fatty Acids is primarily regulated by Carnitine-Acyl-transferase (CPTI)
CPTI is down-regulated by Malonyl-CoA

Muscles will oxidize fatty acids when they need energy.
Muscles will produce Malonyl-CoA (but will not finish synthesizing fatty acids)
 - The purpose of producing Malonyl-CoA is to inhibit the Oxidation of Fatty Acids when energy is high