cataboles

Cataboles, in biology, refer to the set of metabolic processes that break down complex molecules into simpler ones, releasing energy in the process. These catabolic reactions harvest chemical energy stored in macromolecules such as carbohydrates, fats, and proteins and convert it into usable energy carriers like ATP, NADH, and FADH2. Catabolism contrasts with anabolism, the constructive metabolism that builds macromolecules from smaller units, typically consuming energy.

Key catabolic pathways include glycolysis, fatty acid beta-oxidation, proteolysis of proteins to amino acids, and the citric acid cycle, which oxidizes acetyl-CoA to CO2. Through oxidative phosphorylation, electrons carried by NADH and FADH2 drive ATP production. Some catabolic steps occur in the cytosol (glycolysis, glycogenolysis) while others occur in mitochondria (beta-oxidation, the TCA cycle).

Catabolic activity is regulated by cellular energy status and hormones. In mammals, glucagon and epinephrine promote catabolism during fasting or stress, whereas insulin promotes storage and anabolic processes. The balance between catabolism and anabolism supports energy homeostasis, provides substrates for biosynthesis, and enables adaptation to physiological conditions such as exercise or starvation.

Etymology: catabole derives from Greek katabole, meaning a throwing down or breakdown. In basic physiology, cataboles are often discussed together with anaboles as components of metabolism.