The logic of metabolism

SummaryMetabolism is often perceived as a fairly haphazard intertwined collection of chemical compounds that needs to be memorised by heart. The apparent absence of logic in its organisation dissuades most investigators to enter its arcanes. Yet, metabolism, that results from highly selective constraints is logically organised. The atoms of life must build up stable covalent bonds. Symmetry breaking is the rule. Proteinogenic amino acids are of the l-enantiomer type, and this will imply that carbohydrates are of the d-type. Water is ubiquitous because it favours entropy-driven shaping of macromolecules. Then, being the bathing medium of life, hydrolysis is the driving force in orientating pathways. Phosphates, in water, are metastable towards hydrolysis, and this makes them the ultimate energy quantum and currency. Making a variety of reactive molecules in the same retort implies either compartmentalisation or a protection/deprotection procedure, as in the laboratory of all chemists.