13 14 #3. What is the purpose of the SDS in the tyrosinase activity assay? 15 16 17 The SDS is present in order to denature the proteins in the reaction so that tyrosinase can work better. The SDS is an activator of tyrosinase activity, mimicking the action of the fatty acids present in vivo. The SDS is used to make tyrosine more available to the active site on the tyrosinase enzyme.