Distribution of acid sphingomyelinase in human various body fluids.

Enzyme activities of acid sphingomyelinase (ASM) were determined in various human cell-free body fluids, serum, cerebrospinal fluid, urine, salivary fluid, tear fluid, and synovial fluid, using assay buffers with or without Zn2+ -cation. Although ASM activity was not detected in the cerebrospinal fluid, the other fluids demonstrated significant enzyme activities of ASM. All ASMs detected in the fluids were stimulated by the addition of Zn2+ -cation, suggesting that those enzymes are secretory ASM derived from ASM gene. We suggest a possible enzymatic diagnosis of Niemann-Pick disease types A and B using those body fluids. Interestingly, salivary and tear fluids showed much higher activities of ASM than those of the other fluids. Because sphingolipids, especially sphingomyelin, are major constituents of a normal diet, especially, milk, eggs, and meat products, we suggest that ASM in the salivary gland may play an important role in the digestion of sphingomyelin in a normal diet.

[1]  A. Nilsson,et al.  Digestion of ceramide by human milk bile salt-stimulated lipase. , 1998, Journal of pediatric gastroenterology and nutrition.

[2]  K. Williams,et al.  The Cellular Trafficking and Zinc Dependence of Secretory and Lysosomal Sphingomyelinase, Two Products of the Acid Sphingomyelinase Gene* , 1998, The Journal of Biological Chemistry.

[3]  M. Hengartner,et al.  Caenorhabditis elegans Contains Two Distinct Acid Sphingomyelinases* , 1998, The Journal of Biological Chemistry.

[4]  K. Williams,et al.  Human Vascular Endothelial Cells Are a Rich and Regulatable Source of Secretory Sphingomyelinase , 1998, The Journal of Biological Chemistry.

[5]  K. Williams,et al.  Zn2+-stimulated Sphingomyelinase Is Secreted by Many Cell Types and Is a Product of the Acid Sphingomyelinase Gene* , 1996, The Journal of Biological Chemistry.

[6]  T. Mak,et al.  CD28 signals through acidic sphingomyelinase , 1995, The Journal of experimental medicine.

[7]  R. Testi,et al.  Apoptotic signaling through CD95 (Fas/Apo-1) activates an acidic sphingomyelinase , 1994, The Journal of experimental medicine.

[8]  M. Krönke,et al.  Functional dichotomy of neutral and acidic sphingomyelinases in tumor necrosis factor signaling , 1994, Cell.

[9]  H. Ide,et al.  Inflammatory cytokines and enzymes in synovial fluid of patients with rheumatoid arthritis and other arthritides. , 1992, International archives of allergy and immunology.

[10]  R. Desnick,et al.  Identification of a missense mutation (S436R) in the acid sphingomyelinase gene from a Japanese patient with type B Niemann–Pick disease , 1992, Human mutation.

[11]  R. Desnick,et al.  Human acid sphingomyelinase. Isolation, nucleotide sequence and expression of the full-length and alternatively spliced cDNAs. , 1991, The Journal of biological chemistry.

[12]  S. Chatterjee,et al.  Purification of neutral sphingomyelinase from human urine. , 1991, Methods in enzymology.

[13]  N. J. Van Haeringen,et al.  Clinical biochemistry of tears , 1981 .

[14]  R. Brady,et al.  The metabolism of sphingomyelin. II. Evidence of an enzymatic deficiency in Niemann-Pick diseae. , 1966, Proceedings of the National Academy of Sciences of the United States of America.