Peridinin Peridinin Peridinin is a light-harvesting apocarotenoid, a pigment associated with chlorophyll and found in the peridinin-chlorophyll-protein (PCP) light-harvesting complex in dinoflagellates, best studied in "Amphidinium carterae". Peridinin is an apocarotenoid pigment that some organisms use in photosynthesis. Many photosynthetic dinoflagellates use peridinin, which absorbs blue-green light in the 470-550nm range, outside the range accessible to chlorophyll molecules. The peridinin-chlorophyll-protein complex is a specialized molecular complex consisting of a boat-shaped protein molecule with a large central cavity that contains peridinin, chlorophyll, and lipid molecules, usually in a 4:1 ratio of peridinin to chlorophyll. Peridinin chlorophyll (PerCP) is commonly used in immunoassays
Thylakoid centers, each consisting of an antenna complex that uses chlorophylls and accessory photosynthetic pigments such as carotenoids and phycobiliproteins to harvest light at a variety of wavelengths. Each antenna complex has between 250 and 400 pigment molecules and the energy they absorb is shuttled by resonance energy transfer to a specialized chlorophyll "a" at the reaction center of each photosystem. When either of the two chlorophyll "a" molecules at the reaction center absorbs energy, an electron is excited and transferred to an electron-acceptor molecule. Photosystem I contains a pair of chlorophyll "a" molecules, designated P700, at its reaction center that