Arylsulphatase activity of Haliotis rufusensis has been tested at different temperatures and pH. This enzyme is characterized by an optimum temperature at +50°C. The maximum pH activity is depending on temperature; by increasing temperature from +20 to + 50°C, a shift of pH maximum has been observed towards the acidic side. The enzyme activity was tested with nitrocatecholsulphate, synthetic substrato, and with natural substrates, cerebroside sulphate and ascorbate 2-sulphate. These naturai substrates are "competitive" with respect to thè synthetic substrate. Nitrophenylphosphate is a powerful inhibitor of this enzyme; this effect is pH dependent. Several phosphoderivatives, including inositol-phosphatides and myo-inositolphosphate, are also important inhibitors. Arylsulphatase from Haliotis, like those from Heìix and Palella, is a glycoprotein (muramyl-glycoprotein). Its electrophoretic behaviour is similar to that of arylsulphatase A from human liver, but AgNÒ3 or NaCl treatment are ineffective in differentiating A and B forms.
Regulation of arylsulphatases: inhibition of arylsulphatase from Haliotis rufusensis by phosphoric esters and shift of optimal pH depending on temperature / E., Davolio; L., Landini; Volpi, Nicola; M. G., Dubois; M., Masson; Pederzoli, Aurora; L., Bolognani. - In: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY. - ISSN 0305-0491. - STAMPA. - 84B (3):(1986), pp. 261-267.