PYRUVATE KINASE TYPE III FROM RABBIT MUSCLE (C005B-437946)

General description

Pyruvate Kinase (PK) is a glycolysis enzyme and has four isozymes L, R, M₁, and M₂. The L isozyme is localized in gluconeogenic tissues, particularly in the liver. Whereas the R and M₁ are localized in the adult skeletal muscles, heart, brain and erythrocytes, respectively. M₂ is localized in the nucleus of the cells.

Application

Pyruvate Kinase from rabbit muscle has been used to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP) in Pseudomonas putida cells.

Pyruvate kinase has been used in plant spectrophotometric assays to measure ATP hydrolysis . Pyruvate kinase is also used to study pyruvate kinase (PK) deficiency .

Biochem/physiol Actions

Molecular Weight: 237 kDa and exists as a tetramer of four equal subunits of molecular weight 57 kDa.
Isoelectric Point: 7.6
Optimal pH: ∼7.5
Optimal Temperature: 25°C
ΕA₂₈₀ = 0.54 for 1 mg(p)/ml, 1 cm path
Reported K_M values are ATP (0.86 mM), pyruvate (10 mM), ADP (0.3 mM), and PEP (0.07 mM) in Tris buffer at pH 7.4 and 30 °C. Pyruvate kinase is highly specific for phosphoenolpyruvate, but can utilize other dinucleotide triphosphates as substrates in place of ATP including GTP, ITP, dATP, UTP, and CTP.

Pyruvate kinase (PK) catalyzes an important process of transferring phosphate group from phosphoenolpyruvate (PEP) to adenosine diphosphate (ADP). This reaction results in the conversion of PEP to pyruvate and adenosine triphosphate (ATP). Pyruvate kinase plays a major role in glycolysis and gluconeogenesis. High levels of pyruvate kinase M2 (PKM2) inhibits cell proliferation and tumor growth. Deficiency of PK in red blood cells (RBC) leads to non-spherocytic hemolytic anaemia. In human erythrocytes, deficiency of PK induces a protective effect against Plasmodium falciparum.

Unit Definition

One unit will convert 1.0 μmole of phospho(enol)pyruvate to pyruvate per min at pH 7.6 at 37 Ã‚°C.

Analysis Note

Protein determined by biuret.