While typically regarded as a mere waste product of heme breakdown, evidence that suggests that biliverdin – and other bile pigments – has a physiological role in humans has been mounting.

Some studies have found that people with higher concentration levels of bilirubin and biliverdin in their bodies have a lower frequency of cancer and cardiovascular disease.

[4] It has been suggested that biliverdin – as well as many other tetrapyrrolic pigments – may function as an HIV-1 protease inhibitor[6] as well as having beneficial effects in asthma[5] though further research is needed to confirm these results.

[10] Biliverdin is also present in the green blood, muscles, bones, and mucosal lining of skinks of the genus Prasinohaema, found in New Guinea.

It has been suggested that accumulation of biliverdin might deter harmful infection by Plasmodium malaria parasites, although no statistically significant correlation has been established.

[15] Jellyfish- and coral-derived fluorescent proteins require oxygen and produce a stoichiometric amount of hydrogen peroxide upon chromophore formation.

smURFP has a large extinction coefficient (180,000 M−1 cm−1) and has a modest quantum yield (0.20), which makes it comparable biophysical brightness to eGFP and about 2-fold brighter than most red or far-red fluorescent proteins derived from coral.