In biochemistry, a metabolon is a temporary structural-functional complex formed between sequential enzymes of a metabolic pathway, held together by non-covalent interactions, and structural elements of the cell such as integral membrane proteins and proteins of the cytoskeleton. The formation of metabolons allows passing (channelling) the intermediary metabolic product from an enzyme directly as substrate into the active site of the consecutive enzyme of the metabolic pathway. The citric acid cycle is an example of a metabolon which facilitates substrate channeling. During the functioning of metabolons, the amount of water needed to hydrate the enzymes is reduced and enzyme activity is increased. The concept of structural-metabolic cellular complexes was first conceived in 1970 by A. M. Kuzin of the USSR Academy of Sciences, and adopted in 1972 by P. A. Srere of the University of Texas for the enzymes of the citric acid cycle. This hypothesis was well accepted in the former USSR and further developed for the complex of glycolytic enzymes (Embden-Meyerhof-Parnas pathway) by B.I. Kurganov and A.E. Lyubarev. In the mid-1970s, the group of F.M. Clarke at the University of Queensland, Australia also worked on the concept. The name “metabolon” was first proposed in 1985 by P. Srere during a lecture in Debrecen, Hungary.