This linear tetrapyrrole (FW = 559.64 g/mol) is a prosthetic group of blue, highly fluorescent photoreceptor pigments (phycocyanins) found in certain algae. It is soluble in water and polar organic solvents. Phycocyanins, found in Cyanophyta, are proteins, which typically contain three molecules of covalently bound phycocyanobilin per subunit. One molecule of phycocyanobilin is bound per molecule of allophycocyanin, found in Cyanophyta and Rhodophyta. Phycocyanins and their chromophore phycocyanobilin are peroxy radical scavengers and inhibits ONOO–- mediated biological effects. Target(s): cyclooxygenase-2, inhibited by C-phycocyanin and poorly by phycocyanobilin.
