Sterolsulphate sulphohydrolase from human placenta microsomes - 30 kDa molecular weight form of cholesterol sulphate sulphohydrolase

The cholesterol sulphate sulphohydrolase (CHS-ase) exhibiting molecular weight of 30kDa was purified from human placenta microsomes. The microsomal proteins were extracted with 0.5% Triton X-100. The DEAE-cellulose chromatography of the solubilized microsomal proteins. performed at pH 7.6 allowed to separate two enzymatically active fractions, One of them was associated with the protein fraction unbound by DEAE-cellulose. the other was tightly bound by ion exchanger. The 30kDa cholesterol sulphate sulphohydrolase was purified to homogenity from the protein fraction tightly bound by DEAE-cellulose. The highly purified enzyme preparation (specific activity 385 nmol min(-1) mg(-1) of protein) exhibited optimal activity at pH 6.4. the K-m was established to be 6.7 x 10(-6) M. the pI value was 7.4. The 30 kDa cholesterol sulphate sulphohydrolase, in contrast to the CHS-ase form originated from the protein fraction unbound by DEAE-cellulose, was not sensitive to alkaline phosphatase treatment and phosphohydrolase inhibitors. The effects of steroids. -SH reactingagents and sulphohydrolase inhibitors on the enzyme activity were tested. (C) 2002 Published by Elsevier Science Ltd.