Endotoxins (Lipopolysaccharides) are found in preparations of DNA or proteins produced by gram-negative bacteria. Traces of endotoxins are sufficient to induce an inflammatory response. Thus, preparations need to be tested for endotoxins prior to in vitro or in vivo use. LONZA provides a kit that uses the activation of an enzyme found in the blood of horseshoe crabs by endotoxins. The activated enzyme cleaves a colorless peptide and releases the absorbing p-nitroaniline. The time to reach an absorbance threshold is negative proportional to the amount of endotoxin and is used for endotoxin quantitation. Using standards for a calibration curve between 0.005-5.0 endotoxic units results in a linear curve that can be used to determine endotoxin concentration of unknown samples.
Lonza's kinetic kit for endotoxin detection using BMG LABTECH's microplate reader and MARS data analysis
Chris Quinlan, Carl Peters BMG LABTECH 07/2012