Luciferase Firefly
Description
Luciferase is fused to a 21 amino acid His-tag at N-terminus & purified by proprietary chromatographic techniques.
Product Specs
Product Science Overview
Firefly luciferase was first isolated from the common eastern firefly, Photinus pyralis. The enzyme’s ability to produce light through the oxidation of luciferin in the presence of ATP and oxygen has fascinated scientists for decades . The reaction produces a flash of yellow-green light with an emission peak around 560 nm .
Firefly luciferase is a single polypeptide chain with a molecular weight of approximately 61 kDa . The enzyme catalyzes the oxidation of luciferin, a heterocyclic compound, to oxyluciferin, producing light in the process. This reaction requires ATP and magnesium ions (Mg²⁺) as cofactors .
The enzyme’s structure includes several key residues that are essential for its catalytic activity. These residues help in binding the substrate and stabilizing the reaction intermediates . The enzyme’s active site is highly conserved among different species of fireflies, indicating its evolutionary significance .
Recombinant firefly luciferase is typically produced using an Escherichia coli expression system . The gene encoding the luciferase enzyme is cloned into a plasmid vector, which is then introduced into E. coli cells. The bacteria are cultured, and the luciferase protein is expressed and purified using various chromatography techniques .
The recombinant enzyme is usually supplied in a buffered solution containing Tris-acetate, ammonium sulfate, glycerol, ethylene glycol, EDTA, and DTT . This preparation ensures the stability and activity of the enzyme during storage and use.
The bioluminescent reaction catalyzed by firefly luciferase occurs in two main steps :
- Adenylation of Luciferin: Luciferin reacts with ATP to form luciferyl adenylate and pyrophosphate (PPi).
- Oxidation of Luciferyl Adenylate: The luciferyl adenylate complex reacts with molecular oxygen to produce oxyluciferin, AMP, CO₂, and light.
The light produced in this reaction is due to the formation of oxyluciferin in an electronically excited state, which then returns to its ground state by emitting a photon .
Firefly luciferase has become a widely used reporter protein in various biological assays. Its ability to produce light in a highly specific and quantifiable manner makes it an excellent tool for studying gene expression, cell viability, and ATP quantification . The enzyme’s bioluminescent properties have also been harnessed for in vivo imaging and other diagnostic applications .
