L-Lactic Dehydrogenase from rabbit muscle Type II, ammonium sulfate suspension, 800-1,200 units/mg protein

Synonym (S)-Lactate: NAD+ oxidoreductase

L-LDH

LAD

LD

CAS Number 9001-60-9

Descriptions

Analysis Note ………………………..Protein determined by biuret.

Biochem/physiol Actions …. ................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.

Physical form ………………………..Crystalline suspension in 3.2 M (NH4)2SO4 solution, pH 6.0

General description ………………….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 .

Properties

type ………………………………….Type II

form …………….……………………ammonium sulfate suspension

foreign activity………...………........….pyruvate kinase, myokinase, malic dehydrogenase, glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase and α-glycerophosphate dehydrogenase <0.01%

storage temp. 2-8°C