Galactosyltransferase is a type of
glycosyltransferase
Glycosyltransferases (GTFs, Gtfs) are enzymes ( EC 2.4) that establish natural glycosidic linkages. They catalyze the transfer of saccharide moieties from an activated nucleotide sugar (also known as the "glycosyl donor") to a nucleophilic glycos ...
which
catalyzes
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
the transfer of
galactose
Galactose (, '' galacto-'' + '' -ose'', "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molec ...
. An example is
.
The biosynthesis of disaccharides, oligosaccharides and polysaccharides involves the action of hundreds of different glycosyltransferases. These enzymes catalyse the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates () and related proteins into distinct sequence based families has been described.
This classification is available on the CAZy (Carbohydrate-Active EnZymes) web site.
The same three-dimensional fold is expected to occur within each of the families. Because 3-D structures are better conserved than sequences, several of the families defined on the basis of sequence similarities may have similar 3-D structures and therefore form 'clans'.
Glycosyltransferase family 31
CAZY GH_31 comprises enzymes with a number of known activities; N-acetyllactosaminide beta-1,3-N-acetylglucosaminyltransferase (); beta-1,3-galactosyltransferase (); fucose-specific beta-1,3-N-acetylglucosaminyltransferase (); globotriosylceramide beta-1,3-GalNAc transferase ().
Human galactosyltransferases
B3GALNT1
UDP-GalNAc:beta-1,3-N-acetylgalactosaminyltransferase 1 is an enzyme that in humans is encoded by the ''B3GALNT1'' gene.
This gene is a member of the beta-1,3-galactosyltransferase (beta3GalT) gene family. This family encodes type II membrane-bou ...
;
B3GALNT2;
B3GALT1;
B3GALT2;
B3GALT4
Beta-1,3-galactosyltransferase 4 is an enzyme that in humans is encoded by the ''B3GALT4'' gene.
This gene is a member of the beta-1,3-galactosyltransferase (beta3GalT) gene family. This family encodes type II membrane-bound glycoproteins with di ...
;
B3GALT5
Beta-1,3-galactosyltransferase 5 is an enzyme that in humans is encoded by the ''B3GALT5'' gene.
This gene is a member of the beta-1,3-galactosyltransferase (beta3GalT) gene family. This family encodes type II membrane-bound glycoproteins with di ...
;
B3GALT6;
B3GNT2
UDP-GlcNAc:betaGal beta-1,3-N-acetylglucosaminyltransferase 2 is an enzyme that in humans is encoded by the ''B3GNT2'' gene.
This gene encodes a member of the beta-1,3-N-acetylglucosaminyltransferase family. This enzyme is a type II transmembrane ...
;
B3GNT3
UDP-GlcNAc:betaGal beta-1,3-N-acetylglucosaminyltransferase 3 is an enzyme that in humans is encoded by the ''B3GNT3'' gene.
This gene encodes a member of the beta-1,3-N-acetylglucosaminyltransferase family. This enzyme is a type II transmembrane ...
;
B3GNT4;
B3GNT5;
B3GNT6;
B3GNT7;
B3GNT8;
B4GALNT1;
B4GALNT2;
B4GALNT3;
B4GALNT4;
B4GALT1
Beta-1,4-galactosyltransferase 1 is an enzyme that in humans is encoded by the ''B4GALT1'' gene.
This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have excl ...
;
B4GALT2
Beta-1,4-galactosyltransferase 2 is an enzyme that in humans is encoded by the ''B4GALT2'' gene.
This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have excl ...
;
B4GALT3
Beta-1,4-galactosyltransferase 3 is an enzyme that in humans is encoded by the ''B4GALT3'' gene.
This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have excl ...
;
B4GALT4
Beta-1,4-galactosyltransferase 4 is an enzyme that in humans is encoded by the ''B4GALT4'' gene.
This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have excl ...
;
B4GALT5
Beta-1,4-galactosyltransferase 5 is an enzyme that in humans is encoded by the ''B4GALT5'' gene.
This gene is one of seven beta-1,4-galactosyltransferase (beta4GalT) genes. They encode type II membrane-bound glycoproteins that appear to have excl ...
;
B4GALT6;
B4GALT7
Beta-1,4-galactosyltransferase 7 also known as galactosyltransferase I is an enzyme that in humans is encoded by the ''B4GALT7'' gene. Galactosyltransferase I catalyzes the synthesis of the glycosaminoglycan-protein linkage in proteoglycans. Prot ...
;
GALNT1;
GALNT2;
GALNT3
Polypeptide N-acetylgalactosaminyltransferase 3 is an enzyme that in humans is encoded by the ''GALNT3'' gene.
This gene encodes UDP-GalNAc transferase 3, a member of the polypeptide GalNAc transferase (GalNAc-T) family. This family transfers an ...
;
GALNT4;
GALNT5;
GALNT6;
GALNT7;
GALNT8;
GALNT9;
GALNT10;
GALNT11;
GALNT12;
GALNT13;
GALNT14;
GALNTL1;
GALNTL2;
GALNTL4;
GALNTL5;
GALNTL6;
References
External links
*
Transferases
EC 2.4.1
{{2.4-enzyme-stub