N-terminal Early set domain associated with the catalytic domain of prokaryotic glycogen branching enzyme
This subfamily is composed of predominantly prokaryotic 1,4 alpha glucan branching enzymes, also called glycogen branching enzymes. E or "early" set domains are associated with the catalytic domain of glycogen branching enzymes at the N-terminal end. Glycogen branching enzyme catalyzes the formation of alpha-1,6 branch points in either glycogen or starch by cleavage of the alpha-1,4 glucosidic linkage, yielding a non-reducing end oligosaccharide chain, as well as the subsequent attachment of short glucosyl chains to the alpha-1,6 position. By increasing the number of non-reducing ends, glycogen is more reactive to synthesis and digestion as well as being more soluble. The N-terminal domain of the 1,4 alpha glucan branching enzyme may be related to the immunoglobulin and/or fibronectin type III superfamilies. These domains are associated with different types of catalytic domains at either the N-terminal or C-terminal end and may be involved in homodimeric/tetrameric/dodecameric interactions. Members of this family include members of the alpha amylase family, sialidase, galactose oxidase, cellulase, cellulose, hyaluronate lyase, chitobiase, and chitinase, among others.
Jiyao W et al.(2023). "The conserved domain database in 2023.",