Peridinin-chlorophyll-protein complex (PerCP) is a photosynthetic accessory pigment isolated from dinoflagellates that is useful for fluorescence applications. Of particular note is its large Stokes shift; it is excited at 477 nm and emits at 678 nm. This large Stokes shift enables far-red detection using the common blue (488 nm) laser, making PerCP and its tandems ideal companions for FITC and PE in multicolor panels. PerCP tandem conjugates leverage FRET to produce acceptor emission in NIR regions through coupling with cyanine dyes (Cy5.5, Cy7) or iFluor® acceptors, enabling emission wavelengths spanning 678–806 nm while maintaining single-laser (488 nm) excitation.

The spectral properties table below provides excitation and emission maxima and filter configurations for each PerCP tandem conjugate. These specifications enable optimal instrument setup and facilitate panel design for multicolor flow cytometry experiments.

ReadiUse™ preactivated PerCP tandems are supplied in reactive formats ready for direct conjugation to antibodies and other proteins. These preactivated conjugates eliminate the need for separate activation chemistry, streamlining the labeling workflow while delivering higher conjugation yields than traditional approaches.

Amine-reactive PerCP tandems target primary amines (lysine residues and N-termini) present on antibodies and proteins. This chemistry provides straightforward conjugation without requiring antibody reduction, preserving disulfide bonds critical for maintaining antibody structure and binding activity. The amine-reactive format often achieves higher conjugation yields compared to thiol-reactive SMCC chemistry.

SMCC-activated PerCP tandems react specifically with free thiol groups generated by mild reduction of antibody disulfide bonds. This site-directed conjugation approach targets the hinge region of IgG antibodies, positioning the fluorophore away from antigen-binding sites. While requiring an additional reduction step, thiol-reactive chemistry offers controlled stoichiometry for applications demanding consistent labeling ratios.

Buccutite™ technology achieves almost 100% conjugation yield without purification using two proprietary crosslinkers (MTA + FOL) that react rapidly upon mixing. This click chemistry approach overcomes the limitations of conventional SMCC-based conjugation, which often results in protein aggregation and low recovery with sensitive phycobiliproteins like PerCP. The streamlined workflow requires only two incubation steps: addition of the MTA linker to the antibody (30 minutes) followed by addition of the FOL-activated PerCP tandem (60 minutes). The resulting conjugate is immediately ready for use in flow cytometry, immunofluorescence, or immunoassay applications without additional purification. Kits containing 1 mg of PerCP tandem include a spin column for optional buffer exchange and concentration.

A classic three-color panel using only the 488 nm laser may be designed as follows. This design takes advantage of the long Stokes shift seen in PerCP tandems.