Lipid oxidation Flashcards
What are 3 locations for oxidation in liver?
1) Peryoxysomal B oxidation
2) Mitochondrial B oxidation
3) ER Ω-oxidation (CYP4a catalysed)
When does peripheral FA mobilisation occur? G and I?
Glucagon high
Insulin low
What cell component is responsible for peroxisomal beta oxidation?
Ribosomes
What occurs during peroxisomal beta oxidation?
1) Genetic code translated into chains of amino acids
2) Ribosome recognise structure of mRNA bond to tRNA
3) 2 subunits start synthesising a new protein
4) Ribosome act as catalyst
5) Ribosome deposits protein in ER
6) Undergoes further modification
7) 3 – 5 amino acids/ second in protein production
When is mitochondrial Beta Oxidation used?
Oxidation FA’s various chain lengths
What is function mitochondrial beta oxidation?
1) Progressive shortening into acetyl-CoA subunits
2) Condensed into ketone bodies
3) Providing oxidisable energy to cells
4)Enter tricarboxyl acid cycle
5) Result in H2O and CO2
acetyl coA
Ketone
Tricarboxyl acid cycle
What regulates mitochondrial beta oxidation? (3)
CPT (carnitine palmitosyl transferase)
Carnitine concentration
Malonyl-CoA (which inhibits CPT)
If alcohol and genetic disorders inhibit mitochondrial oxidation what can it cause?
Hepatic steatosis
When does ER microsomal Ω –oxidation occur?
Fat overload
Outline process of ER Microsomal Ω –oxidation?
1) CYP4A enzymes oxidise saturated and unsaturated fatty acids
2) Ω-hydroxylation in ER
3) Decarboxylation of Ω-hydroxy fatty acid in cytosol
4) Enter the β-oxidation pathway
5) Dicarboxyl FA act as ligands to PPARά (regulate lipid metabolism)
6) Induction of the oxidation systems
In ER Microsomal Ω –oxidation where does decarboxylation of Ω-hydroxy fatty acid occur?
Cytosol
Function of PAR receptors?
Modify lipid metabolism
