Lactic acid

Lactic acid (α-hydroxypropionic acid) is a chemical compound that plays a role in several biochemical processes.

Biology

Lactic acid accumulates in skeletal muscles during extensive anaerobic exercise, causing temporary muscle pain. Lactic acid is quickly removed from muscles when they resume aerobic metabolism. Delayed onset muscle soreness usually becomes apparent more than 24 hours after exercising and is not caused by lactic acid buildup.

Related Topics:
Muscle - Anaerobic exercise - Aerobic metabolism - Delayed onset muscle soreness

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During one form of anerobic glycolysis or fermentation, L-lactate is produced from pyruvate via the enzyme lactate dehydrogenase. This conversion also oxidizes one molecule of NADH to NAD+, and this is the reason for the conversion: NAD+ has to be regenerated so that glycolysis can continue.

Related Topics:
Anerobic glycolysis - Fermentation - Pyruvate - Enzyme - Lactate dehydrogenase - Oxidizes - NADH

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This lactic acid fermentation occurs in red blood cells since they don't have mitochondria, and in skeletal muscle during intense exertion when sufficient amounts of oxygen cannot be supplied fast enough. This lactate is released into the bloodstream. The typical lactate concentration in the blood is 1-2 mmol/L. The liver takes up about 60% of the lactate and reoxidizes it to pyruvate, which is then reconverted to glucose in a process known as gluconeogenesis. The glucose enters the bloodstream and can be used by the tissues. This glucose → lactate → glucose cycle, originally described by Carl and Gerty Cori, is known as the Cori cycle. About 40% of the lactate is taken up by well oxygenated muscle cells and oxidized to pyruvate, which is then directly used to fuel the citric acid cycle.

Related Topics:
Red blood cell - Mitochondria - Muscle - Oxygen - M - Mol - L - Liver - Glucose - Gluconeogenesis - Carl - Gerty Cori - Cori cycle - Citric acid cycle

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Lactic acid fermentation is also performed by lactic acid bacteria. These bacteria can operate in the mouth; the acid they produce is responsible for the tooth decay known as caries.

Related Topics:
Lactic acid bacteria - Tooth - Caries

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In medicine, lactate is one of the main components of Ringer's lactate or lactated Ringer's solution. This intraveinous fluid consists of sodium, chloride, potassium, and lactate in solution with distilled water in concentration so as to be isotonic compared to human blood. It is most commonly used for fluid resuscitation after blood loss due to trauma, surgery or a burn injury.

Related Topics:
Ringer's lactate - Intraveinous - Isotonic - Human blood - Fluid resuscitation - Trauma - Surgery

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