Fatty Acid Catabolism Lecture Notes

A set of vocabulary flashcards covering the mobilization, transport, and mitochondrial $$\beta$$-oxidation pathway of fatty acids based on the lecture by Dr. Hira.

Triacylglycerols (TAGs)

The dietary source that provides about one-third of our energy needs and is stored in white adipose tissue.

Lipases

Enzymes that catalyze the hydrolysis of stored triacylglycerols into fatty acids and glycerol.

Epinephrine

A hormone that triggers the mobilization of triacylglycerols, signaling the message: 'We need energy now'.

Glucagon

A hormone that triggers the mobilization of triacylglycerols, signaling the message: 'We are out of glucose'.

Long-chain fatty acyl CoA synthetase (thiokinase)

An enzyme of the outer mitochondrial membrane that converts fatty acids in the cytosol to their CoA derivative.

$\beta$-oxidation

The major mitochondrial pathway for the catabolism of fatty acids where two-carbon fragments are successively removed from the carboxyl end.

Carnitine shuttle

The transporter mechanism used to carry activated long-chain fatty acids ($>12$ carbons) into the mitochondrial matrix.

Carnitine-mediated entry

The rate-limiting step for the oxidation of fatty acids into the mitochondria.

Palmitate ($C16$)

A 16-carbon fatty acid that undergoes seven passes through the oxidative sequence to be completely oxidized.

Acyl-CoA dehydrogenase (AD)

The enzyme for Step 1 of $\beta$-oxidation that catalyzes the oxidation of an alkane to an alkene, producing a trans double bond.

Electron-transferring flavoprotein (ETF)

The protein that transfers electrons from bound $FAD$ in the first step of $\beta$-oxidation directly to the electron-transport chain.

Enoyl-CoA hydratase

The enzyme for Step 2 of $\beta$-oxidation that catalyzes the hydration of an alkene to yield an alcohol.

$\beta$-hydroxyacyl-CoA dehydrogenase

The enzyme for Step 3 of $\beta$-oxidation that uses $NAD^+$ as a hydride acceptor to dehydrogenate an alcohol.

Acyl-CoA acetyltransferase (thiolase)

The enzyme for Step 4 of $\beta$-oxidation that catalyzes the thiolysis of a carbon-carbon bond to produce Acetyl-CoA.

108 ATP

The total yield of ATP during the full oxidation of one molecule of Palmitoyl-CoA to $CO_2$ and $H_2O$.

Isomerase

An enzyme required for the oxidation of unsaturated fatty acids to convert cis double bonds starting at carbon 3 to trans double bonds.

Reductase

An enzyme required for the oxidation of polyunsaturated fatty acids to reduce cis double bonds that do not start at carbon 3.

Propionyl-CoA

A 3-carbon unit formed during the final pass of $\beta$-oxidation of odd-numbered fatty acids.