Domain of unknown function (DUF1929). Members of this family adopt a secondary structure consisting of a bundle of seven, mostly antiparallel, beta-strands surrounding a hydrophobic core. The 7 strands are arranged in 2 sheets, in a Greek-key topology. Their precise function, has not, as yet, been defined, though they are mostly found in sugar-utilising enzymes, such as galactose oxidase.

C-terminal Early set domain associated with the catalytic domain of galactose oxidase. E or "early" set domains are associated with the catalytic domain of galactose oxidase at the C-terminal end. Galactose oxidase is an extracellular monomeric enzyme which catalyzes the stereospecific oxidation of a broad range of primary alcohol substrates and possesses a unique mononuclear copper site essential for catalyzing a two-electron transfer reaction during the oxidation of primary alcohols to corresponding aldehydes. The second redox active center necessary for the reaction was found to be situated at a tyrosine residue. The C-terminal domain of galactose oxidase 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.

Copine. This family represents a conserved region approximately 180 residues long within eukaryotic copines. Copines are Ca(2+)-dependent phospholipid-binding proteins that are thought to be involved in membrane-trafficking, and may also be involved in cell division and growth.

VWA Copine: Copines are phospholipid-binding proteins originally identified in paramecium. They are found in human and orthologues have been found in C. elegans and Arabidopsis Thaliana. None have been found in D. Melanogaster or S. Cereviciae. Phylogenetic distribution suggests that copines have been lost in some eukaryotes. No functional properties have been assigned to the VWA domains present in copines. The members of this subgroup contain a functional MIDAS motif based on their preferential binding to magnesium and manganese. However, the MIDAS motif is not totally conserved, in most cases the MIDAS consists of the sequence DxTxS instead of the motif DxSxS that is found in most cases. The C2 domains present in copines mediate phospholipid binding.

Glyoxal oxidase N-terminus. This family represents the N-terminus (approximately 300 residues) of a number of plant and fungal glyoxal oxidase enzymes. Glyoxal oxidase catalyzes the oxidation of aldehydes to carboxylic acids, coupled with reduction of dioxygen to hydrogen peroxide. It is an essential component of the extracellular lignin degradation pathways of the wood-rot fungus Phanerochaete chrysosporium.