55. Biochemistry - Lipid Metabolism II Beta Oxidation

Liver synthesizes TAGs from glycerol and fatty acids. It uses glycerol kinase to directly phosphorylate glycerol and acyltransferases to assemble the TAG molecule.

Dietary TAGs are broken down, absorbed, and reassembled in enterocytes. Fatty acids are attached to CoA, then transferred to 2-monoacylglycerol to form TAGs.

An enzyme that phosphorylates glycerol, crucial for TAG synthesis in liver.

Adipocytes synthesize TAG from fatty acids and glycerol-3-phosphate, predominantly from glucose metabolism.

Insulin promotes fatty acid uptake and glycerol-3-phosphate production in adipocytes, enhancing TAG synthesis.

Amphiphilic particles transporting newly synthesized dietary TAGs in the bloodstream.

Liver-derived TAGs are packaged into VLDL for transport to other tissues.

The process of breaking down stored triglycerides (TAGs) into fatty acids and glycerol to be used for energy.

The breakdown of triglycerides (TAGs) into fatty acids and glycerol.

Rate-limiting enzyme in TAG mobilization; hydrolyzes TAGs only.

Hydrolyzes both TAGs and diacylglycerols (DAGs); its activity is regulated by hormones.

A protein coating lipid droplets in adipocytes; regulates access of lipases to TAGs.

Phosphorylation of perilipin exposes sites in lipid droplet coating, allowing lipases to access TAGs.

Hormones that stimulate lipolysis by increasing cAMP and activating PKA.

Inhibits TAG lipolysis by downregulating ATGL and dephosphorylating HSL & perilipin

Body tissue that serves as a major storage site of triglycerides.

Short-chain fatty acids (SCFA) are transported in the blood without a carrier.

Medium-chain fatty acids (MCFA) use albumin for transport in blood.

Long-chain fatty acids (LCFA) are transported bound to the protein albumin.

LCFAs use the carnitine shuttle to cross the mitochondrial inner membrane.

Enzyme that transfers an LCFA from CoA to carnitine (rate-limiting step for b-oxidation).

Enzyme that catalyzes FA transfer to CoA inside the mitochondria.

Saturated fatty acyl-CoA are broken down into acetyl-CoA, with oxidation from acyl end to methyl end.

Very long chain fatty acids (VLCFA) are broken down in peroxisomes before entering the mitochondria.

The slowest step in a metabolic pathway

Malonyl-CoA inhibits CAT1.

Produces 1 FADH2 molecule during the first step of fatty acid breakdown.

Yields 1 NADH molecule in the third step of fatty acid breakdown.

Yields 8 acetyl-CoAs, along with other breakdown products, following complete oxidation of palmitoyl-CoA.

Results in acetyl-CoA and propionyl-CoA when undergoing b-oxidation in step 4.

Converts propionyl-CoA to succinyl-CoA in three steps, crucial for entering the TCA cycle.

The first step in Beta-oxidation, where an alkane is converted to an alkene, introducing a double bond between carbons 2 and 3. It's catalyzed by acyl-CoA dehydrogenase.

Enzyme catalyzing the addition of water to the alkene double bond in b-oxidation, forming a hydroxyl intermediate.

Enzyme catalyzing the oxidation of the alcohol to a ketone, producing NADH.

Enzyme that cleaves the fatty acyl chain, releasing acetyl-CoA and shortening the chain for subsequent rounds of b-oxidation.

The beta-oxidation process repeats, removing two-carbon fragments at each cycle, until the entire fatty acid is oxidized.

The beta-oxidation pathway is efficient for fully saturated fatty acids with an even number of carbons.

Beta-oxidation is linked to oxidative phosphorylation, meaning the electron transport chain is essential for the process.

An isoform of Acyl-CoA dehydrogenase responsible for b-oxidation of long-chain fatty acids.

An isoform of Acyl-CoA dehydrogenase responsible for b-oxidation of medium-chain fatty acids.

An isoform of Acyl-CoA dehydrogenase responsible for b-oxidation of short-chain fatty acids.