turacin

File:Red feather pigments.jpg wing, left) compared to carotenoids (Ramphocelus bresilius belly, right). Green in center is due to turacoverdin.]]

Turacin is a naturally occurring red pigment that is 6% copper complexed to uroporphyrin III. Arthur Herbert Church discovered turacin in 1869.{{cite journal|jstor=109012|pages=627–636|last1=Church|first1=A. H.|title=Researches on Turacin, an Animal Pigment Containing Copper|volume=159|journal=Philosophical Transactions of the Royal Society of London|year=1869|doi=10.1098/rstl.1869.0024|doi-access=free}}

It is found only in the bird family Musophagidae, the turacos.[http://cancerweb.ncl.ac.uk/cgi-bin/omd?turacin Online Medical Dictionary] Other birds derive their red coloration from carotenoids (bright and orange-reds) or phaeomelanins (rusty and brownish-reds).

It is often assumed that this coloration will wash out when the birds are bathing or after heavy rains, but this is true only if the water used for bathing happens to be very alkaline.

The copper(II) uroporphyrin III pigment in turaco feathers was studied using electron spin resonance by Jack Peisach first with Blumberg{{cite journal |last1=Blumberg |first1=W.E. |last2=Peisach |first2=J. |title=An Electron Spin Resonance Study of Copper Uroporphyrin III and Other Touraco Feather Components |journal=Journal of Biological Chemistry |date=February 1965 |volume=240 |issue=2 |pages=870–876 |doi=10.1016/S0021-9258(17)45255-0 |doi-access=free |pmid=14275147 }} and later with Mims.{{cite journal |last1=Peisach |first1=J. |last2=Mims |first2=W.B. |title=The Linear Electric Field Effect in Stellacyanin, Azurin and in Some Simple Model Compounds |journal=European Journal of Biochemistry |date=March 1978 |volume=84 |issue=1 |pages=207-214 |doi=10.1111/j.1432-1033.1978.tb12158.x |doi-access=free }}