Purification and characterization of a binding protein related to the Z class of cytosolic proteins in guinea-pig liver cytosol (guinea-pig Z protein).
The purification and characterization of a low-molecular-mass binding protein from female guinea-pig liver cytosol is reported. Its molecular mass (14.4 kDa), amino acid composition, abundance and biological properties identify it as belonging to the Z class of liver cytosolic proteins [Levi, A.J., Gatmaitan, Z. & Arias, I.M. (1969) J. Clin. Invest. 48, 2956-2167]. Among the most important members of this class of proteins are the fatty-acid-binding proteins (FABPs) and the sterol carrier protein2 (SCP2). The guinea-pig Z protein (G-ZP) has some similarities in its amino acid composition and NH2-terminal sequence with those of the rat liver FABP, but its isoelectric point is basic (pI 8.85), like that of SCP2. We also examined its binding affinities for a number of ligands bound by these two proteins. The results show that the purified G-ZP binds dehydroepiandrosterone sulfate, estrone sulfate, oleic acid and cholesterol, but shows no affinity for free steroids such as estrone and DHEA. Thus it can be said that G-ZP has some characteristics of FABPs and some of SCP2 but seems, however, to be different from both these proteins. The purified G-ZP inhibits microsomal DHEA sulfate sulfatase activity in a mixed noncompetitive way. This protein could be involved in the transport and/or metabolism of sulfated steroids.
Nicollier
M
M
Unité de Biochimie Hormonale et des Régulations, INSERM U 198, Besançon, France.
Roblin
S
S
Cypriani
B
B
Remy-Martin
J P
JP
Adessi
G L
GL
D000595:Amino Acid Sequence; D000818:Animals; D001192:Arylsulfatases / Q000037:antagonists & inhibitors; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002850:Chromatography, Gel; D003593:Cytoplasm / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D005260:Female; D006168:Guinea Pigs; D007525:Isoelectric Focusing; D008099:Liver / Q000378:metabolism; D008861:Microsomes / Q000201:enzymology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010940:Plant Proteins; D011247:Pregnancy; D012689:Sequence Homology, Nucleic Acid; D013261:Sterols / Q000378:metabolism; D043266:Steryl-Sulfatase
D002352:Carrier Proteins; C490174:Fabp7 protein, rat; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; D010940:Plant Proteins; D013261:Sterols; C072087:sterol carrier proteins; D001192:Arylsulfatases; D043266:Steryl-Sulfatase