, or 1,2,4-trihydroxyanthraquinone
, is a naturally occurring red/yellow dye in the roots of the plant madder
(or known as Rubia tinctorum L). Purpurin also occurs in madder with alizarin
. Purpurin is a crystalline
compound with the formula of C14
that is colorless until dissolved in alkalic
solutions. It is soluble in ethanol
(becomes red) and is soluble in water at boiling and alkalis water (becomes yellow). It has the appearance of dark red needles. It is also called Verantin
, Smoke Brown G
, Hydroxylizaric acid
, and C.I. 58205
Purpurin is a fast dye for cotton printing and forms complexes with various metal ions.
As relating to biochemistry, purpurin is a glycosaminoglycan binding protein as well as a retinol binding protein. Purpurin's pattern of sequences has shown it to belong to the lipocalin family of proteins.
- The Lipocalins: A Review. The Edward Jenner Institute for Vaccine Research.