lactate dehydrogenase

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lactate dehydrogenase

 (LD, LDH) [lak´tāt de-hi´dro-jĕ-nās]
an enzyme that catalyzes the interconversion of lactate and pyruvate. It is widespread in tissues and is particularly abundant in kidney, skeletal muscle, liver, and myocardium. It has five isoenzymes denoted LD1 to LD5. The “flipped” pattern in which the serum LD1 level is greater than the LD2 level is indicative of an acute myocardial infarction. This pattern occurs within 12 to 24 hours after the attack.

lac·tate de·hy·dro·gen·ase (LDH),

name for a number of enzymes, including: l-lactate dehydrogenase (cytochrome), d-lactate dehydrogenase (cytochrome), l-lactate dehydrogenase, and d-lactate dehydrogenase. The first two enzymes transfer hydrogen to ferricytochrome c or to cytochrome b2, the last two transfer it to NAD+, in catalyzing the oxidation of lactate to pyruvate; the isozyme distribution of heart and muscle lactate dehydrogenase is of significant use in cases of myocardial infarction; a deficiency of a subunit will result in myoglobinuria after intense exercise.

lactate dehydrogenase

n. Abbr. LDH
Any of a class of enzymes that catalyze the reversible interconversion of pyruvate and lactate, found predominantly in the liver, kidneys, skeletal muscle, heart muscle, and red blood cells.

lactate dehydrogenase (LDH)

an enzyme that is found in the cytoplasm of almost all body tissues, where its main function is to catalyze the oxidation of l-lactate to pyruvate. It is assayed as a measure of anaerobic carbohydrate metabolism and as one of several serum indicators of myocardial infarction and muscular dystrophies. Serum levels of LDH usually rise 12 to 18 hours after myocardial cell necrosis. See also aspartate aminotransferase, CK isoenzyme fraction, Duchenne's muscular dystrophy.

lactate dehydrogenase

Cardiology An oxidoreductase present in the cytoplasm of all cells that catalyze Lactate + NAD+ ↤ Pyruvate + NADH + H+, the equilibrium of which favors lactate + NAD+ at neutral pH; LD1 is classically ↑ in acute MI, peaking by post-infarct day 4, and associated with a flip in normal ratio of LD1 and LD2. See Flipped LD, LD6. Cf CK-MB, Troponin I, Troponin T.

lac·tate de·hy·dro·gen·ase

(LDH) (lak'tāt dē'hī-droj'ĕn-ās)
Name for four enzymes. The first two transfer H to ferricytochrome c; the last two transfer it to NAD+, in catalyzing the oxidation of lactate to pyruvate; the isozyme distribution of heart and muscle lactate dehydrogenase is of diagnostic use in myocardial infarction.

lactate dehydrogenase (LDH)

One of the cell enzymes released into the blood when heart muscle cells are damaged during a heart attack (myocardial infarction). A measure of the concentration of these enzymes can indicate the severity of the attack.

lac·tate de·hy·dro·gen·ase

(LDH) (lak'tāt dē'hī-droj'ĕn-ās)
Name for four enzymes; of diagnostic use in myocardial infarction.

lactate dehydrogenase

(lak´tāt dē´hīdroj´ənās´),
n an enzyme found in the cytoplasm of almost all body tissues, where its main function is to catalyze the oxidation of L-lactate to pyruvate.

lactate

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

lactate dehydrogenase
called also LD, LDH; see lactate dehydrogenase.
lactate dehydrogenase test
a high level in milk used as an indicator of the presence of mastitis in the quarter.
exercise blood lactate
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.
lactate 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.
lactate Tm
maximal tubular concentration of lactate.