Description
A lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells (animals, plants, and prokaryotes). LDH catalyzes the conversion of pyruvate to lactate and back, as it converts NADH to NAD+ and back. A dehydrogenase is an enzyme that transfers a hydride from one molecule to another.
Applications
This enzyme is useful for enzymatic determination of numerous metabolites, e.g.ATP, ADP, glucose, creatinine, pyruvate, lactate and glycerol, and of enzyme activities, e.g.GPT, PK and CPK when coupled with the related enzymes.
Appearance
White amorphous powder, lyophilized
Enzyme Commission Number
EC 1.1.1.28
Activity
GradeⅡ 400U/mg-solid or more
Contaminants
NADH oxidase < 1.0×10⁻³% Malate dehydrogenase < 1.0×10⁻²% GOT < 5.0×10⁻³% GPT < 5.0×10⁻³% Myokinase < 1.0×10⁻²% Pyruvate kinase< 1.0×10⁻³%
Molecular Weight
approx. 140 kDa (by gel filtration)
pH Stability
pH 5.0-9.0 (25°C, 48hr)
Michaelis Constant
1.6×10⁻⁴M (pyruvate, pH 7.0)
Optimum temperature
35-40°C
Thermal stability
below 45°C (pH 7.0, 15min)
Inhibitors
Ag⁺, Hg⁺⁺, SH-reagents
Synonyms
Lactate dehydrogenase; EC 1.1.1.27; LDH; LD
