Cholesterol sulphate sulphohydrolase from human placenta microsomes — purification and properties of the dephosphorylated form of enzyme

Cholesterol sulphate sulphohydrolase of human placenta lysosomal membrane

“…This value of K M points out the high affinity of the purified CHS-ase to cholesterol sulphate as substrate. It is similar to the values established for steroid sulphohydrolases by other authors, ranging from 1.4 to 7.27 × 10 −5 mol/l [3,7,12,40,44,49]. However, some of these values were established with the use of substrate different than cholesterol sulphate.…”

“…enzyme or enzyme-detergent complexes. The differences in molecular weight of CHS-ase may also arise from polymerization and depolymerization process provoked by phosphorylation and dephosphorylation of the enzymatic protein [7]. The molecular weight 38 kDa of purified lysosomal CHS-ase described in this paper is comparable with the mass 30 kDa established for microsomal CHS-ase from human placenta [8].…”

“…The molecular weight of steroid sulphohydrolases ranges from 23 to 1000 kDa [3,7,8,[10][11][12]40,[42][43][44]. The molecular weight variants may represent proteolytically modified enzymes, heterogeneously glycosylated forms of the same The following proteins were used as pI markers: 1, amyloglucosidase (pI 3.6); 2, trypsin inhibitor from soybean (pI 4.6); 3, carbonic anhydrase II from bovine erythrocytes (pI 5.9); 4, myoglobin (pI 7.2); 5, lectin from Lens culinaris (pI 8.8); 6, trypsinogen (pI 9.3).…”

“…The pH 3.4 is typical for lysosomal enzymes acting in acidic environment. However, the majority of steroid sulphohydrolases reveal the pH optimum about value 6.0-9.0 [3,7,8,10,12,[44][45][46][47]. According to Noël et al [11], microsomal steroid sulphohydrolase with cholesterol sulphate as substrate revealed two pH optima, one at pH 5.0 and another at pH 7.5.…”

“…Nevertheless, it is evident that isoenzymes of steroid sulphohydrolase with more selective or absolute substrate preference exist [3][4][5][6][7][8][9]. Alternative expression of distinct exons of the gene or diverse posttranslational modifications may explain the existence of distinct forms of STS with different biological activity (substrate specificity) and subcellular localization.…”