Biliprotein
[2] Biliproteins found in plants and algae serve as a system of pigments whose purpose is to detect and absorb light needed for photosynthesis.
[4] According to a 2002 article written by Takashi Hirata et al., the chromophores of certain phycobiliproteins are responsible for antioxidant activities in these biliproteins, and phycocyanin also possesses anti-inflammatory qualities due to its inhibitory apoprotein.
When induced by both collagen and adenosine triphosphate (ADP), the chromophore phycocyanobilin suppresses platelet aggregation in phycocyanin, its corresponding phycobiliprotein.
Functions such as preventing cellular damage, regulating guanylyl cyclase with biliverdin, among other roles associated with metabolic maintenance, have been hypothesised but yet to be proven.
[3] The structural changes involved in deriving bilins from their biliverdin IXα isomer determine the spectral range of light absorption.
Some special qualities of phycobiliproteins include antioxidant properties and high fluorescence, and it is their chromophores that give these proteins their strong pigment.
The fractions with isoelectric points at or around 4.6 seemed analogous to phytochromes in that they possessed photochromic properties, yet were sensitive to light of shorter wavelengths.
This information is then transduced via intracellular signaling pathways that trigger responses specific to the organism and its development state on both cellular and molecular levels, as explained by Quail.
[6] In a 1988 study conducted by Hugo Scheer and Harmut Kayser, biliproteins were extracted from the large white butterfly and puss moth and their respective properties were examined.
[7] The study cited from M. Bois-Choussy and M. Barbier that these IXγ-series bile pigments are derived from cleavage of the porphyrin precursors at the C-15 (formerly γ) methine bridge, which is uncharacteristic of other mammalian and plant biliproteins.
When the scientists examined biliproteins from both the large white butterfly and puss moth, they found that their polypeptides had a low α-helix content in comparison to phycobiliproteins.
[6] Based on these examinations, it was concluded that insect biliproteins are only loosely related to those from plants and algae, due to the large number of differences they have regarding structure, chemical composition, derivation of bilins and general functions.
Given their large range of applications and potential uses, researchers have been trying to find and develop ways to produce and purify phycobiliproteins to meet the growing demand for them.
[citation needed] The fluorescence signals emitted from phycoerythrin and phycocyanin have made them suitable for use as indicators to detect cyanotoxins such as microcystins in drinking water.
The test results showed that the biliproteins have an early warning function against microcystins in conventional treatment stages that use pre-oxidation with permanganate, activated carbon and chlorination.
