IDK® Tryptophan ELISA High Sensitive

The IDK® Tryptophan ELISA High Sensitive (Mouse/Rat) is intended for the quantitative determination of L-tryptophan in EDTA plasma, serum, and brain tissue of rodents (mouse, rat), and in cell culture supernatant and CSF.

For research use only. Not for use in diagnostic procedures.

For Laboratory Professional Use Only.

Developed by Immundiagnostik AG.

Test Principle of the IDK® Tryptophan ELISA

IDK® Tryptophan ELISA High Sensitive is based on the method of competitive enzyme-linked immunoassays. The sample preparation includes the addition of a derivatization reagent for L-tryptophan derivatization. Afterward, the treated samples and a polyclonal L-tryptophan antiserum are incubated in the wells of a microtiter plate coated with L-tryptophan derivative (tracer).

During the first incubation period, the target L-tryptophan in the sample competes with the tracer, immobilized on the wall of the microtiter wells, for the binding of the polyclonal antibodies. The L-tryptophan in the sample displaces the antibodies out of the binding to the tracer.

During the second incubation step, a peroxidase-conjugated antibody is added to each microtiter well to detect the L-tryptophan antibodies. After washing away the unbound components, tetramethylbenzidine (TMB) is added as a peroxidase substrate. Finally, the enzymatic reaction is terminated by an acidic stop solution. The color changes from blue to yellow, and the absorbance is measured in a photometer at 450 nm. The intensity of the yellow color is inversely proportional to the tryptophan concentration in the sample. This means, a high L-tryptophan concentration in the sample reduces the concentration of tracer-bound antibodies and lowers the photometric signal.

A dose-response curve of the absorbance unit (optical density, OD at 450 nm) vs. concentration is generated using the values obtained from the standard. The presence of L-tryptophan in the samples is determined directly from this curve.