N-terminal Early set domain associated with the catalytic domain of esterase
E or "early" set domains are associated with the catalytic domain of esterase at the N-terminal end. Esterases catalyze the hydrolysis of organic esters to release an alcohol or thiol and acid. The term esterase can be applied to enzymes that hydrolyze carboxylate, phosphate and sulphate esters, but is more often restricted to the first class of substrate. The N-terminal domain of esterase 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.