IRDye QC-1 Quencher is the first non-fluorescent quencher that can
efficiently quench fluorescence from a wide range of fluorophores
from the visible to near-infrared regions (from approximately
500 to 800 nm) in a fluorescence resonance energy transfer
(FRET) system. For the first time, you do not need to carefully
match the donor’s
fluorescence spectrum and the acceptor’s absorption spectrum
to determine which acceptor is suitable for your FRET application(s).
Just pair the IRDye QC-1 with the visible or near-infrared
fluorophore within the wide wavelength range of the quencher.
IRDye
QC-1 is a water-soluble, monoreactive NHS ester dye, which
allows it to be used to label peptides, proteins, nucleic acids,
etc., through the amine group on such molecules. A water-soluble
quencher simplifies the labeling and purification process.
Protease substrates using the IRDye QC-1 do not require
an organic co-solvent in assay buffer systems.
IRDye QC-1
is suitable for FRET-based applications such as protease assays.
IRDye QC-1 was used to develop LI-COR’s IRDye HIV-1
Protease Assay Kit and IRDye Beta-Secretase Assay Kit.
Ordering Information:
| Part # | Description | Unit/Size | Downloads | Order Online |
| 929-70030 | IRDye QC-1 NHS Ester 0.5 mg
Non-fluorescent dye that efficiently quenches fluorescence from a wide range of fluorophores from the visible to near-infrared regions (500-800 nm). | | description
msds
pack insert
| $ 120.00
 |
| 929-70031 | IRDye QC-1 NHS Ester 5.0 mg
Non-fluorescent dye that efficiently quenches fluorescence from a wide range of fluorophores from the visible to near-infrared regions (500-800 nm). | | description
msds
pack insert
| $ 850.00
|
Application Example: IRDye® HIV-1 Protease Assay
The IRDye HIV-1
Protease Assay, as outlined in Figure 1, is based on a highly
quenched IRDye 800CW / IRDye QC-1 NIR-FRET peptide substrate.
Figure 1. The principle of the IRDye HIV-1 Protease Assay.
Figure 2. Measurement of HIV-1 protease activity (error bars are ± standard
deviation). HIV-1 Protease peptide substrate (20 μL/well at final
concentration of 1.0 μM) was titrated with 20 μL/well of recombinant
HIV-1 protease from final concentrations of 0.312 nM to 320 nM. The
plate was incubated at 37 °C for 1 hour. The reactions were then
stopped with 200 μL/well of HIV-1 protease stop solution. The
fluorescence intensity was measured on an Aerius® Automated Infrared
Imaging System (LI-COR Biosciences).
Figure 3. Inhibition of HIV-1 protease by a characterized inhibitor,
Pepstatin A, in a 96-well plate. The serially diluted inhibitor
solutions (10 μL/well at final concentrations from 4.11 to 9000
nM) were mixed with HIV-1 protease (10 μL/well at final concentration
of 20 nM) for 15 minutes before adding substrate (20 μL/well at
final concentration of 1.0 μM). After incubating at 37 °C
for 1 hour, the reactions were stopped with 200 μL/well of HIV-1
protease stop solution. The fluorescence intensity was measured on
an Aerius Automated Infrared Imaging System.
NOTE: Additional application
examples using IRDye QC-1 Quencher and IRDye 800CW can be found
in the data sheet for LI-COR’s IRDye Beta-Secretase Assay Kit,
available at www.licor.com.
