- 1Human α-L iduronidase from liver was purified about 20 000-fold with a new rapid three-step, five-column procedure which consisted of a Concanavalin-A–Sepharose/Blue-A–Agarose coupled step, a CM-Sepharose/Bio-Gel HT coupled step followedby a cupric-ion-chelating Sepharose 6B step.
- 2The behaviour of α-L-iduronidase on gel permeation chromatography was dependent upon both pH and ionic strength of the eluting buffer. The formation of species with enzyme activity which behaved as large-molecular-mass aggregates was favoured under conditions of low ionic strength and neutral pH. The amount of high-Mr species diminished as the pH decreased or the ionic strength increased to favour a single active species of Mr 65000.
- 3A specific monoclonal antibody was generated against liver α-L-iduronidase. The antibody specifically immunoprecipitated enzyme activity from both crude and purified sources.
- 4The subunit Mr of liver α-L-iduronidase was estimated to be 65000 using SDS-PAGE. Monoclonal antibody immunoprecipitation of radiolabelled enzyme was used to provide definitive confirmation of this subunit size.