July 12, 2016

By: douano@listlabs.com

By: Nancy Shine, Ph.D., Director of Research & Development

List Biological Laboratories, Inc. has designed a fluorescently labeled substrate for specific and quantitative detection of anthrax lethal factor in plasma.

Bacillus anthracis is regarded as a major biological warfare threat. The inhalation form of Bacillus anthracis infection can kill quickly. While antibiotic treatment can clear the bacterium from the host, if diagnosis is delayed, the toxin, which is rapidly produced, may already be present in lethal amounts. There is a critical need for a rapid, accurate, sensitive and simple assay to determine whether infection has occurred thereby allowing immediate treatment.

MAPKKide® Plus for Anthrax Detection in Plasma

The use of MAPKKide® Plus allows for a fast, sensitive, specific and accurate method to detect active infection by Bacillus anthracis in plasma. Anthrax lethal factor (LF), an endopeptidase, is present in blood early in the infection. The use of peptidic substrates in plasma is problematic due to the presence of other proteases and the likelihood of nonspecific cleavage of the substrate. MAPKKide® Plus is a fluorescently labeled peptide substrate which is not cleaved by plasma proteases and thus is specific for LF.

Methods for Using MAPKKide® Plus

There are two methods to use MAPKKide® Plus for anthrax detection. One method involves the enrichment of LF by capture from plasma using an LF antibody-coated microtiter plate, and the captured LF is then exposed to MAPKKide® Plus. The amount of cleaved peptide substrate is determined by HPLC with fluorescence detection. Concentration of the LF using the antibody-coated plates allows for the detection of 5 pg LF/ml of neat plasma after 2 hours of incubation. Alternately the MAPKKide® Plus may be added directly to diluted plasma and cleavage monitored by an increase in fluorescence as a function of time using a fluorescent microplate reader. The limit of detection by this simpler method is 1 ng LF/ml of plasma after 5 hours of digestion. Both methods can be confirmed by analysis of the reaction as a function of time.

MAPKKide® Plus details are as follows:

• Product: #532
• Price per vial: $250
• Vial size: 100 nmoles
• Not a Select Agent or a controlled export item
• A patent application has been filed for this peptide substrate.

MAPKKide® Plus is in its final stages of release and will be available from stock early next month. We are accepting orders now. Orders may be placed online on the product detail page.

Please do not hesitate to contact us with any other questions about MAPKKide® Plus. More information about all List Labs products and potential future products can be found on the following pages:

• Seach all Research Reagent Products
• Product Pipeline