In order to keep cells alive and healthy, an array of several interlinked reactions takes place inside cells and is referred to as metabolism.

There are two major classes of metabolism, building up complex substrate molecules from smaller molecules is known as anabolism.

Whereas, breakdown of complex molecules into small molecules is termed catabolism.

Definition of Amphibolic Pathway

The pathway that includes both catabolism and anabolism is termed amphibolic pathway. Davis introduced this term in 1961.

Example of Amphibolic Pathway

Kreb cycle is an ideal example of the amphibolic pathway because it involves carbohydrate and fatty acid catabolism and synthesis of the precursor molecules for amino acid synthesis.

Krebs cycle comprises sequences of chemical reaction which oxidize acetyl Co-A final pathways for oxidation of carbohydrate, lipid, and protein in the mitochondrial matrix.

The initiation of cycle begins with the anabolic condensation of acetyl Co-A and oxallo-acetate to synthesize citric acid. Subsequently, two molecules of CO2 exit and regenerates oxaloacetate to continue the other cycle.

Krebs Cycle: Definition, Diagram, Steps, and Mechanism

Anaplerosis and Cataplerosis

• The set of reactions in which cytosol intermediates of metabolism enter the citric acid cycle. The replenishment of oxaloacetate for the condensation with acetyl-CoA in TCA cycle by pyruvate carboxylation is known as an anaplerotic reaction.

• Cataplerosis is a series of reaction in which intermediates enters cytosol and leave citric acid cycle.

Significance of Amphibolic Pathways

Amphibolic pathways are batteries of chemical reactions which exhibit the transformation of many metabolites which are end products of catabolism and the precursors of anabolism.

Amphibolic Pathway Citations

• Impaired mitochondrial metabolism and reduced amphibolic Krebs cycle activity in diabetic rat hepatocytes. Biochem Mol Biol Int . 1995 Dec;37(6):1079-89.