Chemiluminescence cofactors

In general, a chemiluminescent reaction can be generated by two basic mechanisms (Fig. 2). In a direct reaction, two reagents, usually a substrate and an oxidant in the presence of some cofactors, react to form a product or intermediate, sometimes in the presence of a catalyst. Then some fraction of the product or intermediate will be formed in an electronically excited state, which can subse-... 

A Ca +-binding protein isolated from jellyfish Aequorea sp.) that is frequently used as a chemiluminescent calcium indicator.Aequorin contains a hydrophobic prosthetic group, coelenterazine. Investigators have been able to express the transfected gene recombinantly in a number of cells, and upon addition of the cofactor, one can measure intracellular calcium concentration. See Fura-2... 

An indirect chemiluminescence immunoassay is an assay, with another component than the primary chemiluminescent emitter coupled to the antigen or antibody. This can be a cofactor or a catalyst or even a molecule capable of converting a non-chemiluminescent precursor to a chemiluminescent or potentially chemiluminescent species. Most indirect assays are enzyme mediated. 

Fluorophore Chemiluminescent Enzyme Cofactor Lysing agent Secondary label Prosthetic group Electroactive Spin label Substrate... 

Chemiluminescence offers a useful alternative to both fluorescence and radioactivity, as it does not require an excitation source, there is less light scattering, and the problem of source instability is absent. The radiation hazard is also absent from chemiluminescent molecules. Most chemiluminescent reagents and their conjugates are stable and can be applied to both homogeneous and heterogenous assays. The chemiluminescent label may be attached to an enzyme or may serve either as a substrate or as a cofactor for the enzyme. 

Calcium oxalate monohydrate (25-250 treatment of proximal (LLC-PKl) and distal (MDCK) tubular epitheUal cell cultures increased superoxide production 3-6-fold as measured by both lucigenin chemiluminescence in permeabil-ized cells and dihydrorhodamine fluorescence in intact cells (Khand etal. 2002). The use of mitochondrial probes, substrates, and inhibitors indicated that increased Oj " production originated from mitochondria. Treatment with calcium oxalate monohydrate decreased glutathione (total and redox state), indicating a sustained oxidative insult. An increase in NADH in calcium oxalate monohydrate-treated cells suggested this cofactor could be responsible for elevating O2 generation. 

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