Laktaattiionin

Laktaattiionin, in scientific usage, refers to the lactate ion, the conjugate base of lactic acid and a common metabolic intermediate. Its chemical formula is C3H5O3−, and in solution it exists primarily as the lactate form of lactic acid (pKa about 3.86). In biological systems it occurs in two enantiomeric forms, L-lactate and D-lactate, with L-lactate predominating in human metabolism.

Biological role: It is produced from pyruvate by the enzyme lactate dehydrogenase during anaerobic glycolysis or impaired oxygen supply. The isoforms LDH-5 (muscle) and other tissues catalyze this reaction. Lactate can be transported out of cells by monocarboxylate transporters and utilized by other tissues, notably the heart and liver, via the Cori cycle to be converted back to glucose. Lactate is also a signaling metabolite affecting gene expression and metabolic regulation.

Clinical and industrial relevance: In medicine, lactate is encountered in balance solutions such as lactated Ringer's solution, which contains sodium lactate as a buffering component. Clinically, blood lactate concentration is used as a marker of tissue hypoxia or sepsis; elevated levels can indicate lactic acidosis. In foods, lactate salts (sodium lactate, calcium lactate) function as buffering agents and acidity regulators.

Chemistry: The lactate ion is a weak acid and forms salts with various cations; it forms biodegradable esters and is involved in fermentation. In biological contexts, it serves as a key intermediary between glycolysis and energy production.