Porphyran is a sulfated carbohydrate derived from red algae of the genus Porphyra.
[1] Porphyran is a complex sulfated carbohydrate.
It is a highly substituted complex carbohydrate related to agarose with a linear backbone consisting of 3-linked beta-D-galactosyl units alternating with either 4-linked alpha-L-galactosyl 6-sulfate or 3,6-anhydro-alpha-L-galactosyl units.
[1][2][3][4] The precise composition of porphyran shows seasonal and environmental variations.
[4] Porphyran is converted to agarose by cyclization of L-galactose-6-sulfate to 3,6-anhydro-L-galactose.