Deficiency of seminolipid sulphatase activity in brain tissue of metachromatic leucodystrophy

Seminolipid and its precursor/degradative product, galactosylalkylacylglycerol, in the testis of saposin A- and prosaposin-deficient mice

“…Seminolipid [3-sulfogalactosyl-1-alkyl-2-acylsn -glycerol, galactosylalkylacylglycerol (GalEAG) I 3 -sulfate] is the principal glycolipid in spermatozoa of mammals comprising, for example, approximately 3% of total lipids and more than 90% of total glycolipids in boar spermatozoa (17,18). Seminolipid is synthesized by sulfation of its precursor, GalEAG, by the action of 3 Ј -phosphoadenylylsulfate:cerebroside 3 Ј -sulfotransferase (CST, EC 2.8.2.11) and is degraded to GalEAG by arylsulfatase A, the enzyme missing in metachromatic leukodystrophy (19). GalEAG is synthesized by galactosylation of alkylacylglycerol (EAG) by UDP-galactose:ceramide galactosyltransferase (CGT, EC 2.4.1.62) and is likely to be degraded by galactosylceramidase, which is deficient in globoid cell leukodystrophy.…”

Glycolipid and Glycoprotein Degradation

“…Watersoluble compounds such as 4-methylumbelliferylsulfate and glucose-3-sulfate are optimally hydrolyzed at pH 5.2 (709) and 5.3 (748), respectively, whereas for lipid substrates that include sulfatide (675,709,728,730), seminolipid (756,757), and sulfogalactosylsphingosine (lysosulfatide) (740) the pH optima were usually found to be around pH 4.5. In a few cases, such as high concentration of detergent [5.8-mM sodium taurocholate (727)] or at low ionic strength, in the absence of detergents (730), higher values (pH 5.0 and 5.3, respectively) were determined.…”