The activation of Aspergillus niger catalase by sodium n-dodecyl-sulphate.

In marked contrast to most enzymes it is found that at pH 6.4 the activity of the fungal catalase from Aspergillus niger is increased on binding of sodium n-dodecyl sulphate (SDS). Activation of the enzyme by up to 180% is found under optimum conditions when approx. 150 SDS molecules are bound. Activation does not occur under acid (pH 3.2) or alkaline (pH 10.0) conditions. Sedimentation analysis confirms that the enzyme does not dissociate into subunits at pH 6.4 (or pH 10.0). These observations are considered in the light of other catalase-SDS studies and it is suggested that the binding of SDS to Aspergillus niger catalase at pH 6.4 results in a small conformational change facilitating the enzymic reaction.