How is propionyl-CoA converted to glucose?

Propionyl-CoA is converted to succinyl-CoA, which is oxidized or converted to glucose by way of oxaloacetate and pyruvate (gluconeogenesis; Chapter 14). Succinyl-CoA may also form Δ-aminolevulinate, a precursor of porphyrin biosynthesis (Chapter 17).

How does propionyl-CoA enter into TCA cycle?

Propionyl-CoA carboxylase (PCC) catalyzes the conversion of propionyl-CoA to methylmalonyl-CoA, which enters the Krebs cycle via succinyl-CoA. Sources of propionate include: valine, isoleucine, threonine, methionine, odd-chain fatty acids, and cholesterol.

How is propionyl-CoA metabolized?

Propionyl CoA originates from the catabolism of essential amino acids (valine, threonine, isoleucine, methionine), odd-chain fatty acids, and cholesterol. It is primarily metabolized to methylmalonyl CoA by propionyl-CoA carboxylase (PCC), which, like other carboxylases, requires biotin for activity.

What is the fate of propionyl-CoA from the oxidation of fatty acids with odd number of carbon?

Oxidation of fatty acids with odd numbers of carbons ultimately produces an intermediate with three carbons called propionyl-CoA, which cannot be oxidized further in the beta-oxidation pathway. Metabolism of this intermediate is odd.

What does propionyl-CoA carboxylase do?

Propionyl-CoA carboxylase (PCC) function. PCC’s primary function is to catalyze the carboxylation of propionyl-CoA to produce methylmalonyl-CoA (Fig. 1A). Propionyl-CoA is produced by catabolism of cholesterol, valine, odd chain fatty acids, methionine, isoleucine and threonine (c-VOMIT) [2], [16], [17], [18].

Where does propionyl-CoA go?

Within the citric acid cycle in humans, propionyl-CoA, which interacts with oxaloacetate to form methylcitrate, can also catalyzed into methylmalonyl-CoA through carboxylation by propionyl-CoA carboxylase (PCC). Methylmalonyl-CoA is later transformed to succinyl-CoA to be further used in the tricarboxylic acid cycle.

Which molecule will produce propionyl-CoA during beta oxidation?

Odd-chain fatty acids undergo beta-oxidation in the same manner as even chain fatty acids; however, once a five-carbon chain remains, the final spiral of beta-oxidation will yield one molecule of acetyl CoA and one molecule of propionyl CoA.

What inhibits propionyl-CoA carboxylase?

Unexpectedly, itaconate was a strong inhibitor of acetate and propionate assimilation in isocitrate lyase-negative purple non-sulfur bacterium Rhodospirillum rubrum. It was shown that in cell extracts of R. rubrum itaconate inhibited propionyl-CoA carboxylase (PCC) activity.

How many carbons are in propionyl-CoA?

Propionyl-CoA is a coenzyme A derivative of propionic acid. It is composed of a 24 total carbon chain (without the coenzyme, it is a 3 carbon structure) and its production and metabolic fate depend on which organism it is present in.

How many NADH and FADH2 are produced in beta oxidation?

In each round of β-oxidation, 1 molecule of acetyl-CoA, 1 molecule of NADH, and 1 molecule of FADH2 are produced.

What is the end product of beta oxidation?

IX. Mitochondrial beta-oxidation Beta-oxidation is the process by which long chain fatty acyl CoA is degraded. The products of beta-oxidation are: acetyl CoA. FADH2, NADH and H.

What is the function of propionyl CoA?

Propionyl-CoA is also a substrate for post-translational modification of proteins by reacting with lysine residues on proteins, a reaction called protein propionylation. Due to structural similarities of Acetyl-CoA and Propionyl-CoA, propionylation reaction are thought to use many of the same enzymes used for protein acetylation.

How is propionyl CoA converted to succinyl CoA?

Propionyl-CoA is converted to succinyl-CoA, which is oxidized or converted to glucose by way of oxaloacetate and pyruvate (gluconeogenesis; Chapter 15 ). Succinyl-CoA may also form δ -aminolevulinate, a precursor of porphyrin biosynthesis ( Chapter 29 ).

What is the first step in carboxylation of propionyl CoA?

The first step is carboxylation by the biotin-dependent propionyl CoA carboxylase in an ATP-requiring reaction. The D- isomer, which is the product, is then converted to the L- isomer by methylmalonyl CoA racemase.

Is propionyl CoA toxic to bacteria?

Propionyl-CoA has can have many adverse and toxic affects on different species, including bacterium. For example, inhibition of pyruvate dehydrogenase by an accumulation of propionyl-CoA in Rhodobacter sphaeroides can prove deadly.