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It has previously been demonstrated that CuZn-superoxide dismutase (SOD) is secreted by several human cell lines. This suggests that the circulating enzyme derives from both hemolysis and peripheral tissues as a result of cellular secretion. In the present report, we evaluated the presence of CuZn-SOD in human serum lipoproteins by both enzyme-linked immunosorbent assay and Western blot analysis of immunoprecipitated lipoprotein samples. The distribution of CuZn-SOD activity among the different lipoprotein fractions was also determined by the xanthine/xanthine oxidase method. The results demonstrated that CuZn-SOD is noticeably present in serum lipoproteins and mainly in low and high density lipoproteins (LDL and HDL). Moreover, experiments performed by incubating CuZn-SOD with a lipid emulsion and subsequent separation of the lipid fraction by ultracentrifugation showed that this enzyme associates in a saturable manner with lipids. The CuZn-SOD bound to LDL and HDL could exert a physiological protective role against oxidative damage of these lipoprotein classes that carry out a crucial role in the cholesterol transport.

We report the results over 15 years (1977-1991) for biochemical diagnoses of patients referred from throughout Italy and suspected of having a mucopolysaccharidosis. Of these, 147 patients were diagnosed as being homozygous or hemizygous for a specific lysosomal enzyme deficiency; 74 pregnancies at risk were monitored in their families; 76 heterozygote diagnoses were performed on their relatives, with a total of 48 positive diagnoses. We also report the analysis of genomic DNA from 11 unrelated Italian Hunter patients, using pc2S15 probe. DNA from two patients, digested with Pst-I, showed a variant pattern of hybridization caused by deletion or rearrangement of the gene. © 1993 Society for the Study of Inborn Errors of Metabolism and Kluwer Academic Publishers.