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What is the difference between phycobiliproteins stored in PBS only and those stored in PBS with ammonium sulfate?
Both buffer solutions provide long-term stability for phycobiliproteins (PBPs). However, PBPs stored in PBS with ammonium sulfate require additional purification steps—such as dialysis or sulfate precipitation—to fully remove the ammonium sulfate before use in tandem dye synthesis or antibody conjugation.
Home Algae Biotech offers phycobiliproteins stored in both PBS-only and PBS with ammonium sulfate to suit different research and application needs.
Does the conjugation reaction link R-PE/APC to free sulfhydryl groups on the antibody?
Yes, Home Algae's R-PE & APC Labeling Kit are SH-reactive labeling kits. Crosslinked R-PE and APC contain maleimide (-NH2) groups, which readily react with sulfhydryl (-SH) groups on target antibodies without additional activation. The maleimide group on R-PE/APC forms a stable covalent bond with the antibody’s sulfhydryl group during conjugation.
🔹 Bonus: Users can also label other molecules that contain free sulfhydryl groups using crosslinked R-PE & APC.
Do I need to remove free R-PE from the R-PE conjugate?
After conjugation, the reaction mixture primarily contains R-PE-antibody conjugate with minimal unconjugated R-PE and antibody. Unconjugated R-PE does not interfere with assay results.
🔹 Purification is recommended for labeling up to 1 mg of antibody for optimal performance. Contact us for technical support.
Can I buy a large pack of labeling kits and separate them into smaller vials for multiple reactions?
Yes! Our labeling kits are scalable, allowing you to divide larger packs into small vials based on your experiment requirements.
What are the molecular weights of purified R-PE and APC?
✔ R-PE: 240 kDa
✔ APC: 105 kDa
Both are ideal for detecting cell surface antigens, enabling cell screening and imaging. Their high molecular weight prevents penetration into cells even if the cell membrane ruptures, significantly reducing false-positive reactions.
🔹 Important Note: The high molecular weight of R-PE makes it unsuitable for intracellular staining, as it limits penetration into cells and tissues. It is best suited for surface labeling in flow cytometry applications.