title: Isolation of palmitoyl-CoA hydrolases from human blood platelets.
abstract: The palmitoyl-CoA hydrolase activity, which in human blood platelets is mainly localized in the cytosol fraction [Berge, Vollset & Farstad (1980) Scand. J. Clin. Lab. Invest. 40, 271--279], was found to be extremely labile. Inclusion of glycerol or palmitoyl-CoA stabilized the activity during preparation. Gel-filtration studies revealed multiple forms of the enzyme with molecular weights corresponding to about 70 000, 40 000 and 24 000. The relative recovery of the mol.wt.-70 000 form was increased by the presence of 20% (v/v) glycerol or 10 microM-palmitoyl-CoA. The three enzyme forms are probably unrelated, since they were not interconvertible. The three different species of palmitoyl-CoA hydrolase were purified by DEAE-cellulose and hydroxyapatite chromatography, isoelectric focusing and high-pressure liquid chromatography (h.p.l.c.) to apparent homogeneity. The three enzymes had isoelectric points (pI) of 7.0, 6.1 and 4.9. The corresponding molecular weights were 27 000--33 000, 66 000--72 000 and 45 000--49 000, calculated from h.p.l.c. and Ultrogel AcA-44 chromatography. The apparently purified enzymes were unstable, as most of the activity was lost during purification. The enzyme with an apparent molecular weight of 45 000--49 000 was split into fractions with molecular weights of less than 10 000 by re-chromatography on h.p.l.c. concomitantly with a loss of activity. The stimulation of the activity by the presence of serum albumin seems to depend on the availability of palmitoyl-CoA, as has been reported for other palmitoyl-CoA hydrolases. [Berge & Farstad (1979) Eur. J. Biochem. 96, 393--401].
mesh_terms: D001792:Blood Platelets / Q000201:enzymology*; D002845:Chromatography; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000097:blood* / Q000302:isolation & purification; D008970:Molecular Weight; D010170:Palmitoyl-CoA Hydrolase / Q000097:blood* / Q000302:isolation & purification; D013869:Thiolester Hydrolases / Q000097:blood*
chemical_list: D007527:Isoenzymes; D013869:Thiolester Hydrolases; D010170:Palmitoyl-CoA Hydrolase