Assignment of the gene for human sphingolipid activator protein-2 (SAP-2) to chromosome 10.

Sphingolipid activator protein-2 (SAP-2) has been found to stimulate the enzymatic hydrolysis of glucosylceramide, galactosylceramide, and sphingomyelin. When human skin fibroblast extracts were subjected to sodium dodecylsulfate-polyacrylamide gel electrophoresis followed by electroblotting and immunochemical staining using monospecific antibodies against SAP-2, two or three major bands with estimated mol. wts. of 9,000-10,000 were found. These antibodies did not crossreact with purified SAP-1, another activating protein, or with extracts of CHO-K1 cells. A series of 22 human/Chinese hamster ovary cell hybrids containing different human chromosomes were examined by this method. All eight hybrid clones containing human chromosome 10 were found to have crossreacting protein in this region. Other chromosomes could be excluded by this method. From these results, we conclude that the gene coding for human SAP-2 is located on chromosome 10.