L1254

L-Lactic Dehydrogenase from rabbit muscle

Type XI, lyophilized powder, 600-1,200 units/mg protein

• Synonym(s): Anaerobic Lactate Dehydrogenase, Lactate, NAD-lactate dehydrogenase, (S)-Lactate: NAD⁺ oxidoreductase, L-LDH, LAD, LD
• CAS Number: 9001-60-9
• Enzyme Commission number: 1.1.1.27 (BRENDA, IUBMB)
• EC Number: 232-617-8
• MDL number: MFCD00131466
• UNSPSC Code: 12352204
• NACRES: NA.54

Properties

• biological source: rabbit muscle
• Quality Level: 200
• type: Type XI
• form: lyophilized powder
• specific activity: 600-1,200 units/mg protein
• mol wt: 140 kDa
• composition: protein, 90-100%
• storage condition: (Keep container tightly closed in a dry and well-ventilated place)
• technique(s): activity assay: suitable
• color: white
• foreign activity: pyruvate kinase, myokinase, malic dehydrogenase, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase and α-glycerophosphate dehydrogenase ≤0.01%
• storage temp.: −20°C

Description

General description

Research area: Cell Signaling

Lactic Dehydrogenase (LDH) has a total molecular weight of 140 kDa and is composed of 4 subunits which are designated M subunit (muscle) and H subunit (heart). These subunits may be mixed in any of 5 combinations (M4, M3H1, M2H2, MH3, and H4). Skeletal muscle contains LDH that is predominately M4 with some small amounts of M3H and traces of H2H2. The H and M subunits are quite similar in molecular weight, but differ substantially in amino acid composition. Rabbit muscle LDH dissociates into dimeric species (MW = ~70 kDa) in acetate-chloride at pH 5.0, the dissociation is reversible. Biochemistry, 13, 3527-3531 (1974). Oxidizes glyoxylate and lactate.
Isoelectric point: 8.4-8.6
Optimal pH : 7.5 .

Application

L-Lactic Dehydrogenase from rabbit muscle has been used:

• as a component of activation and relaxing solution in ATPase activity and isometric steady-state tension measurements with muscle fiber
• in Trypanosoma congolense pyruvate kinase activity assay
• in pyruvate kinase (PK) assay with rice plastidic PK enzyme OsPK2

Biochem/physiol Actions

Muscle-type Lactic Dehydrogenase (LDH) participates in metabolic pathways and its activity is essential for anaerobic glycolysis. LDH activity is inhibited by ascorbate. LDH regenerates nicotinamide adenine dinucleotide (NAD⁺) from NADH and is industrially useful in poly(lactic acid) production. In the absence of oxygen, LDH participates in a fermentation reaction, catalyzes pyruvate into lactic acid, and oxidizes nicotinamide adenine dinucleotide (NADH) to NAD⁺. Therefore, LDH mediates the production of NAD⁺ essential anaerobic glycolysis pathway. Through this LDH helps maintain the physiological and biochemical functions of the cell in the absence of oxygen.

Also catalyzes the oxidation of other L-2-hydroxymonocarboxylic acids.

Unit Definition

One unit will reduce 1.0 μmole of pyruvate to L-lactate per min at pH 7.5 at 37 °C.

Analysis Note

Protein determined by biuret.

Safety Information

• Storage Class Code: 11 - Combustible Solids
• WGK: WGK 3
• Flash Point(F): Not applicable
• Flash Point(C): Not applicable
• Personal Protective Equipment: dust mask type N95 (US), Eyeshields, Gloves