Allophycocyanin

To be effectively used in applications such as FACS, High-Throughput Screening (HTS) and microscopy, APC needs to be chemically cross-linked.

Allophycocyanin can be isolated from various species of red or blue-green algae, each producing slightly different forms of the molecule.

[1] The conventional method for accomplishing this is through a destructive process wherein the treated APC trimer is chemically disrupted in 8M urea and then allowed to re-associate through in a physiological buffer.

[2] An alternative method can be used which preserves the structural integrity of the APC trimer and allows for a brighter, more stable end-product.

It is commonly used in immunoassays such as FACS, flow cytometry, and High Throughput Screening as an acceptor for Europium via Time Resolved-Fluorescence Resonance Energy Transfer (TR-FRET) assays.