Caspases play important roles in apoptosis and inflammation. Caspase 1 Staining Kit (Far Red) are used by researchers seeking to quantitate apoptosis via caspase activity in cultured cells. The fluorescent 660-YVAD-FMK caspase-1 inhibitor reagent allows researchers to assess caspase activation.

The fluorescent reagent 660-YVAD-FMK enters each cell and irreversibly binds to activated Caspase 1. Because the 660-YVAD-FMK  reagent becomes covalently coupled to the active enzymes, it is retained within the cell, while any unbound 660-YVAD-FMK reagent diffuses out of the cell and is washed away. The remaining far red fluorescent signal is a direct measure of the active caspase enzyme activity present in the cell at the time the reagent was added. Cells that contain the bound 660-YVAD-FMK can be analyzed by fluorescence microscopy or flow cytometry. Cells labeled with the 660-YVAD-FMK reagent may be read immediately or preserved for 16 hours using the fixative. Unfixed samples may also be analyzed with Hoechst stain to detect changes in nuclear morphology.

The target for this kit is Caspase 1.

NOTE: The number of tests per kit depends on the application being tested. This kit provides 50 tests for flow and 25 for imaging.

Activated caspase enzymes cleave proteins by recognizing a 3 or 4 amino acid sequence that must include an aspartic acid (D) residue in the P1 position. 660-YVAD-FMK caspase-1 inhibitor reagent contains the preferred binding sequence for caspase-1, Tyr-Val-Ala-Asp (YVAD). It should be noted that the YVAD binding sequence is also recognized by caspases 4 and 5. The YVAD binding sequence is labeled at the amino terminus end with a far-red fluorescent 660 dye and linked at the carboxyl end to a fluoromethyl ketone (FMK) reactive entity. The resulting cell permeant fluorescent molecule, 660-YVAD-FMK, optimally excites at 660 nm and emits between 685-690 nm. A conventional red HeNe laser with a 633 nm excitation provides excellent excitation efficiency, enabling cells labeled with 660-YVAD-FMK to be analyzed with most flow cytometers and fluorescence microscopes equipped with electronic grey scale image capabilities.

Kits are available for other caspases:

Poly Caspase Staining Kit (Far Red) (ab270783)

Caspase 3/7 Staining Kit (Far Red) (ab270785)