In this in-vitro study, we want to identify any potential small molecule that can enhance activity in defective IDS in MPS II. This small molecule should have low value of IC50, inhibition constant (Ki) and demonstrate the binding and stabilizing effects of small molecule on IDS. The potential small molecules candidates will be purchased from Iduron, UK. General Objective: To identify potential small molecule as pharmacological chaperone for the treatment of MPS II Specific Objectives a) To determine half maximal inhibitory concentration (IC50s) of the small molecule candidates b) To identify inhibition constant (Ki) of the small molecule candidates using Lineweaver-Burk plots c) To demonstrate the binding and stabilizing effects of small molecule candidates using heat inactivation assay