lactate

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A salt or ester of lactic acid (CH₃CHOHCOOH). In lactates, the acidic hydrogen of the carboxyl group has been replaced by a metal or an organic radical. Lactates are optically active, with a chiral center at carbon 2. Commercial fermentation produces either the dextrorotatory (R) or the levorotatory (S) form, depending on the organism involved. See also Optical activity.

The R form of lactate occurs in blood and muscle as a product of glycolysis. Lack of sufficient oxygen during strenuous exercise causes enzymatic (lactate dehydrogenase) reduction of pyruvic acid to lactate, which causes tiredness, sore muscles, and even muscle cramps. During renewed oxygen supply (rest) the lactate is reoxidized to pyruvic acid and the fragments enter the Krebs (citric acid) cycle. The plasma membranes of muscle and liver are permeable to pyruvates and lactates, permitting the blood to transport them to the liver (Cori cycle). Lactates also increase during fasting and in diabetics.

Lactates are found in certain foods (sauerkraut), and may be used for flour conditioning and in food emulsification. Alkali-metal salts act as blood coagulants and are used in calcium therapy, while esters are used as plasticizers and as solvents for lacquers. See also Ester; Salt (chemistry).

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Salts of lactic acid.

A salt or ester of lactic acid in which a metal or organic radical has replaced hydrogen in the carboxyl group. Lactate is a dissociation product of lactic acid:

CH₃CH (OH)COOH ⇌ CH₃CH(OH)COO⁻ + H⁺

lactic acid ⇌ lactate ions + protons

Dissociation of lactic acid in the blood results in blood lactate. Levels of blood lactate vary, but are usually 1-2 mmol l⁻¹ and increase during anaerobic metabolism as lactic acid is produced. Although lactate concentration is used as a predictor of endurance (see lactate threshold), lactate is not a useless by-product of anaerobic metabolism, but it is an important metabolic fuel used by muscles, especially during exercise. See also lactate shuttle, lactic acid.

1. α-hydroxypropionate; 2-hydroxypropanoate; the anion, CH₃ — CH(OH) — COO⁻, derived from lactic acid. It occurs naturally as d(—)-lactate (i.e. (R)-2-hydroxypropanoate) and l(+)-lactate (i.e. (S)-2-hydroxypropanoate). l(+)-lactate is formed by anaerobic glycolysis in animal tissues, and dl-lactate is found in sour milk, molasses, and certain fruit juices. Bacterial lactic-acid fermentations produce either the d(-) or l(+) enantiomer or the racemate (dl) depending on the individual organism.
2. any salt or carboxylic ester of lactic acid.
3. to secrete milk; see lactation.

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1. any salt of lactic acid or the anion of lactic acid.
2. to secrete milk.

• l. dehydrogenase — called also LD, LDH; see lactate dehydrogenase.
• l. dehydrogenase test — a high level in milk used as an indicator of the presence of mastitis in the quarter.
• exercise blood l. — exercise by a horse begins aerobically without any elevation of blood lactate levels; exercise at faster levels is eventually performed anaerobically and blood lactate levels rise steeply.
• l. shuttle — the production of lactate in resting muscle where adequate oxygenation is available; represents a mechanism for conserving glucose absorbed from the gut by allowing it to be converted to lactate by skeletal muscle and later used for work or transferred to the liver for glycogen synthesis.
• l. T_m — maximal tubular concentration of lactate.

See words rhyming with "lactate."

Dansk (Danish)
1.
v. intr. - amme, die

2.
n. - laktat, mælkesurt salt

Nederlands (Dutch)
lactaat (melkzuurzout), melk afscheiden

Français (French)
1.
v. intr. - produire du lait

2.
n. - lactate

Deutsch (German)
1.
v. - (Biol.) Milch produzieren, Milch absondern

2.
n. - (chem.) Salz od. Ester der Milchsäure, Lactat

Ελληνική (Greek)
n. - γαλακτικό άλας
v. - εκκρίνω γάλα

Italiano (Italian)
lattato, secernere latte

Português (Portuguese)
n. - lactato (m) (Quím.)
v. - lactar

Русский (Russian)
выделять молоко, соль молочной кислоты

Español (Spanish)
1.
v. intr. - lactar

2.
n. - lactato

Svenska (Swedish)
n. - laktat
v. - att producera mjölk i sina bröst

中文（简体）(Chinese (Simplified))
1. 分泌乳汁, 授乳

2. 乳酸盐

中文（繁體）(Chinese (Traditional))
1.
n. - 乳酸鹽

2.
v. intr. - 分泌乳汁, 授乳

한국어 (Korean)
1.
v. intr. - 젖을 분비하다, 수유하다

2.
n. - 락타아제(소화 효소)

日本語 (Japanese)
v. - 乳汁を分泌する
n. - 乳酸塩

العربيه (Arabic)
‏(الاسم) اللكتات, اللبنات, ملح الحامض اللبني (فعل) يفرز اللبن‏

עברית (Hebrew)
v. intr. - ‮היניקה‬
n. - ‮מלח של חומצה חלבית‬

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