GNT1 is a fungal enzyme that belongs to the GT 8 family. N-acetylglucosaminyltransferase is a fungal enzyme that catalyzes the addition of N-acetyl-D-glucosamine to mannotetraose side chains by an alpha 1-2 linkage during the synthesis of mannan. The N-acetyl-D-glucosamine moiety in mannan plays a role in the attachment of mannan to asparagine residues in proteins. The mannotetraose and its N-acetyl-D-glucosamine derivative side chains of mannan are the principle immunochemical determinants on the cell surface. N-acetylglucosaminyltransferase is a member of glycosyltransferase family 8, which are, based on the relative anomeric stereochemistry of the substrate and product in the reaction catalyzed, retaining glycosyltransferases.

galactinol synthase

Alpha-N-acetylglucosamine transferase [Cell envelope biogenesis, outer membrane]

Glycosyl transferase family 8. This family includes enzymes that transfer sugar residues to donor molecules. Members of this family are involved in lipopolysaccharide biosynthesis and glycogen synthesis. This family includes Lipopolysaccharide galactosyltransferase, lipopolysaccharide glucosyltransferase 1, and glycogenin glucosyltransferase.

Glycogenin belongs the GT 8 family and initiates the biosynthesis of glycogen. Glycogenin initiates the biosynthesis of glycogen by incorporating glucose residues through a self-glucosylation reaction at a Tyr residue, and then acts as substrate for chain elongation by glycogen synthase and branching enzyme. It contains a conserved DxD motif and an N-terminal beta-alpha-beta Rossmann-like fold that are common to the nucleotide-binding domains of most glycosyltransferases. The DxD motif is essential for coordination of the catalytic divalent cation, most commonly Mn2+. Glycogenin can be classified as a retaining glycosyltransferase, based on the relative anomeric stereochemistry of the substrate and product in the reaction catalyzed. It is placed in glycosyltransferase family 8 which includes lipopolysaccharide glucose and galactose transferases and galactinol synthases.