ASPA also known as aspartoacylase, is expressed in liver, lung and kidney tissue, as well as in skeletal muscle and in cerebral white matter. Existing as a homodimer, ASPA functions to catalyze the deacetylation of N-acetylaspartic acid (NAA) (a protein whose hydrolysis is crucial to maintenance of intact white matter) to produce acetate and L-aspartate. Recombinant human ASPA, was expressed in E.coli and purified by conventional chromatography techniques.