Gallotannin

A gallotannin is a class of molecules belonging to the hydrolysable tannins. Gallotannins are polymers formed when gallic acid, a polyphenol monomer, esterifies and binds with the hydroxyl group of a polyol carbohydrate such as glucose.

Metabolism

Gallate 1-beta-glucosyltransferase uses UDP-glucose and gallate to produce UDP and 1-galloyl-beta-D-glucose. Beta-glucogallin O-galloyltransferase uses 1-O-galloyl-beta-D-glucose to produce D-glucose and 1-O,6-O-digalloyl-beta-D-glucose. Beta-glucogallin-tetrakisgalloylglucose O-galloyltransferase uses 1-O-galloyl-beta-D-glucose and 1,2,3,6-tetrakis-O-galloyl-beta-D-glucose to produce D-glucose and 1,2,3,4,6-pentakis-O-galloyl-beta-D-glucose (1,2,3,4,6-penta-O-galloyl-β-D-glucose, the common precursor of gallotannins and the related ellagitannins[1]).

Tannase is a key enzyme in tha degradation of gallotannins that uses digallic acid and H2O to produce gallic acid.

See also

References

  1. ^ Biosynthesis of gallotannins: β-Glucogallin-dependent formation of 1,2,3,4,6-pentagalloylglucose by enzymatic galloylation of 1,2,3,6-tetragalloylglucose. Cammann J., Denzel K., Schilling G. and Gross G. G., Archives of Biochemistry and Biophysics, Volume 273, Issue 1, 15 August 1989, Pages 58-63
Types of gallotannins
Aglycones
Examples
Burkinabin A | B | C | Galloyl glucose | Digalloyl glucose | Trigalloyl glucose: 1,2,6-Trigalloyl glucose / 1,3,6,-Trigalloyl glucose (Corilagin) | Tetragalloyl glucose: 1,2,3,6-tetragalloylglucose | Pentagalloyl glucose: 1,2,3,4,6-pentagalloyl-glucose and 6-digalloyl-1,2,3-trigalloyl-glucose | Hexagalloyl glucose | Heptagalloyl glucose | Octagalloyl glucose | Nonagalloyl glucose | Decagalloyl glucose | 1,3,4-Tri-O-galloylquinic acid | 3,4,5-Tri-O-galloylquinic acid | 3,5-di-O-galloyl-shikimic acid | 3,4,5-tri-O-galloylshikimic acid | 1,2,6-trigalloyl alloside | 1,3,6-trigalloyl alloside | 1,2,3,6-tetragalloyl alloside