Streptavidin R-Phycoerythrin Conjugate (SAPE)

Streptavidin R-Phycoerythrin Conjugate (SAPE) is a high-sensitivity fluorescent detection reagent combining the exceptional biotin-binding capacity of streptavidin (Kd ≈ 10⁻¹⁵ M) with the brilliant fluorescence of R-Phycoerythrin (R-PE), one of the brightest fluorophores available for flow cytometry and bioassay applications.

R-PE is a phycobiliprotein derived from red algae with multiple absorption peaks at 496 nm, 546 nm, and 565 nm, and maximum emission at 578 nm, making it ideally suited for excitation by the 532 nm or 561 nm laser lines standard on most flow cytometers.

SAPE is widely used in:

• Flow cytometry (PE channel; excellent signal-to-noise ratio)
• Bead-based multiplex assays (e.g., Luminex xMAP®, Illumina VeraCode®)
• Microarray platforms (e.g., Affymetrix GeneChip®)
• Immunohistochemistry (IHC)
• Microplate-based immunoassays

Previously featured on Luminex's recommended materials list, Flogen SAPE is produced using in-house R-PE raw material under strict QC control, delivering consistent lot-to-lot performance comparable to leading brands. 

SPECS TABLE

Manufactured from In-House R-PE Flogen SAPE is produced using R-PE purified from microalgae cultivated by our parent company FEBICO — one of the few manufacturers worldwide with full upstream control from algae cultivation to final conjugate. This vertical integration is the foundation of our lot-to-lot consistency, eliminating the variability that comes from sourcing raw materials externally.

Consistent Lot-to-Lot Quality Each production batch undergoes strict QC testing including biotin-binding activity verification and fluorescent intensity measurement. Every lot is released against defined acceptance criteria, giving you reliable, reproducible results experiment after experiment.

Five Types to Match Your Sensitivity Requirements SAPE Types I–V differ in PE-to-streptavidin labeling ratio, allowing you to select the appropriate signal intensity for your specific assay — from routine flow cytometry panels (Type I–II) to high-sensitivity microarray and bead-based multiplex applications (Type III–V).

Benchmarked Against Leading Brands Flogen SAPE has been independently validated against Invitrogen SAPE in both sandwich immunoassay and DNA direct hybridization formats. In hybridization assays, Flogen SAPE demonstrated an R² of 0.9853 correlation with Invitrogen SAPE, confirming comparable performance — at a more competitive price point from a direct manufacturer.

Luminex-Recognized Flogen SAPE was previously listed on Luminex's recommended materials list, reflecting its validated performance as a reporter in xMAP® bead-based multiplex platforms.

Scalable Supply for Industrial and OEM Customers With our proprietary large-scale purification process and flexible production capacity, Flogen can reliably supply SAPE from research-scale (1 mg) to industrial OEM quantities (25 mg and above), with custom specifications available on request. 

REFERENCES

R-Phycoerythrin Optical Properties

Glazer, A. N., & Hixson, C. S. (1975). Subunit structure and chromophore composition of rhodophytan phycoerythrin. Journal of Biological Chemistry, 250(14), 5487–5495.

Oi, V. T., Glazer, A. N., & Stryer, L. (1982). Fluorescent phycobiliprotein conjugates for analyses of cells and molecules. Journal of Cell Biology, 93(3), 981–986.

Streptavidin-Biotin Interaction

Chaiet, L., & Wolf, F. J. (1964). The properties of streptavidin, a biotin-binding protein from Streptomyces avidinii. Archives of Biochemistry and Biophysics, 106(1–3), 1–5.

Weber, P. C., Ohlendorf, D. H., Wendoloski, J. J., & Salemme, F. R. (1989). Structural origins of high-affinity biotin binding to streptavidin. Science, 243(4887), 85–88.

SAPE in Flow Cytometry and Multiplex Assays

Fulton, R. J., McDade, R. L., Smith, P. L., Kienker, L. J., & Kettman, J. R. (1997). Advanced multiplexed analysis with the FlowMetrix system. Clinical Chemistry, 43(9), 1749–1756.

Lunde, E., & Christiansen, G. (2005). Phycoerythrin-streptavidin conjugates for use in flow cytometry and fluorescence microscopy. Journal of Immunological Methods, 305(1), 85–92.

SAPE in Microarray Applications

Lockhart, D. J., et al. (1996). Expression monitoring by hybridization to high-density oligonucleotide arrays. Nature Biotechnology, 14(13), 1675–1680.