Lactate Dehydrogenase (LDH)

Molecular Biology / MB-Enzymes, Dehydrogenase

4°C Do Not Freeze

Supplied as a liquid in 20mM Tris-Chloride, 3.1M ammonium sulfate, 1mM DTT, 1mM EDTA, pH 7.5. No preservative added.

Lactate dehydrogenase is also known as L-lactate dehydrogenase A chain, LDH-A, LDH muscle subunit and LDH-M. Two isozymes of LDH occur in mammals, LDH-M and LDH-H which come together to form a homotetramer of 36kD subunits. Every LDH molecule consists of four subunits, where each subunit is either H each M (based on their electrophoretic properties.) There are, therefore, five LDH isotypes: LDH-1 (4H)-in the heart, LDH-2 (3H1M)-in the reticuloendothelial system, LDH-3 (2H2M)-in the lungs, LDH-4 (1H3M)-in the kidneys and LDH-5 (4M) in the liver and striated muscle. Usually LDH-2 is the predominant form in the serum. An LDH-1 level higher than the LDH-2 level (a flipped pattern) suggests myocardial infarction (damage to heart tissues releases heart LDH, which is rich in LDH-1, into the bloodstream). In general, LDH is often used as a marker of tissue breakdown. LDH shows a cytoplasmic localization.

Source:
Human Erythrocytes

CAS No:
9001-60-9

E.C. No:
1.1.1.27

Synonyms:
LDH-1; LD1 isoenzyme; 4H isoenzyme; Lactic Dehydrogenase

Protein (Coomassie):
≥1mg protein/mle)

Specific Activity:
≥500u/ml

Unit Definition:
One unit will catalyze the oxidation of one micromole of L-lactate to pyruvate with simultaneous reduction of NAD+ to NADH per minutes at 37ºC and pH 9.4.

Isoenzyme (Helena QuickGel® LD Isoenzyme Electrophoresis):
LDH-1: > 95%
LDH-2: < 1%
LDH-3: < 1%
LDH-4: < 1%
LDH-5: < 1%
CPK: < 1.0%

Storage and Stability:
May be stored at 4°C. For long-term storage, aliquot and store at 4°C. Do not freeze. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial prior to removing the cap. Further dilutions can be made in assay buffer.