Galactan Explained

Galactan (galactosan) is a polysaccharide consisting of polymerized galactose. In general, galactans in natural sources contain a core of galactose units connected by α(1→3) or α(1→6), with structures containing other monosaccharides as side-chains.^[1]

Galactan derived from Anogeissus latifolia is primarily α(1→6), but galactan from acacia trees is primarily α(1→3).^[2]

Halymenia durvillei is a red seaweed (algae) that produces a sulfated galactan.^[3] Several other algae species also contain galactans. Including Carpopeltis .^[4]

Galactan is found in the side chains of rhamnogalacturonan I (RG-I) and is needed for gel formation in the cell walls of organisms.^[5] It was observed there was less of the gelling characteristic (as well as the polymeric chains being more likely to degrade) when fewer galactans were present in the polymeric side chains. ^[6]

See also

• Agar
• Galactooligosaccharide

Notes and References

1. Book: The Antibodies. Zanetti. Maurizio. Capra. Donald J.. 2003-09-02. . 9780203216514. 78. en.
2. Book: Zanetti . Maurizio . The antibodies . 1995 . Harwood Academic Publishers . Luxembourg . 0-415-28466-X . 78 .
3. Fenoradosoa . T. A. . Delattre . C. . Laroche . C. . Wadouachi . A. . Dulong . V. . Picton . L. . Andriamadio . P. . Michaud . P. . Highly sulphated galactan from Halymenia durvillei (Halymeniales, Rhodophyta), a red seaweed of Madagascar marine coasts . Int J Biol Macromol . 1 August 2009 . 45 . 2 . 140-5 . 10.1016/j.ijbiomac.2009.04.015.
4. I.J. Miller and J. Mollion, Evaluation of the structures of galactans from Carpopeltis sp. a member of the Halymeniales in the western Indian Ocean, Bot. Mar., 49 (2006) 79-85
5. Mikshina . Polina V. . Makshakova . Olga N. . Petrova . Anna A. . Gaifullina . Ilzira Z. . Idiyatullin . Bulat Z. . Gorshkova . Tatyana A. . Zuev . Yuriy F. . September 2017 . Gelation of rhamnogalacturonan I is based on galactan side chain interaction and does not involve chemical modifications . Carbohydrate Polymers . en . 171 . 143–151 . 10.1016/j.carbpol.2017.05.013.
6. Robal . Marju . Truus . Kalle . Volobujeva . Olga . Mellikov . Enn . Tuvikene . Rando . November 2017 . Thermal stability of red algal galactans: Effect of molecular structure and counterions . International Journal of Biological Macromolecules . 104 . 213–223 . 10.1016/j.ijbiomac.2017.05.175 . 0141-8130.