| http://purl.uniprot.org/citations/19224915 | http://www.w3.org/1999/02/22-rdf-syntax-ns#type | http://purl.uniprot.org/core/Journal_Citation |
| http://purl.uniprot.org/citations/19224915 | http://www.w3.org/2000/01/rdf-schema#comment | "Arylsulfatase A (ASA) catalyzes the intralysosomal desulfation of 3-O-sulfogalactosylceramide (sulfatide) to galactosylceramide. The reaction requires saposin B (Sap B), a non-enzymatic proteinaceous cofactor which presents sulfatide to the catalytic site of ASA. The lack of either ASA or Sap B results in a block of sulfatide degradation, progressive intralysosomal accumulation of sulfatide, and the fatal lysosomal storage disease metachromatic leukodystrophy. We studied the coupled Sap B-ASA reaction in vitro using detergent-free micellar and liposomal assay systems and in vivo using cell culture models of metachromatic leukodystrophy. Under in vitro conditions, the reaction had a narrow pH optimum around pH 4.3 and was inhibited by mono- and divalent cations, phosphate and sulfite. Bis(monoacylglycero) phosphate and phosphatidic acid were activators of the reaction, underscoring a significant role of acidic phosphoglycerolipids in sphingolipid degradation. Desulfation was negligible when Sap B was substituted by Sap A, C, or D. Up to a molar ratio between Sap B and sulfatide of 1:5, an elevation of Sap B concentrations caused a sharp increase of sulfatide hydrolysis, indicating the requirement of unexpected high Sap B levels for maximum turnover. Feeding of ASA-deficient, sulfatide-storing primary mouse kidney cells with ASA caused partial clearance of sulfatide. Co-feeding of Sap B or its precursor prosaposin resulted in the lysosomal uptake of the cofactor but did not promote ASA-catalyzed sulfatide hydrolysis. This suggests that Sap B is not a limiting factor of the coupled Sap B-ASA reaction in mouse kidney cells even if sulfatide has accumulated to unphysiologically high levels."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.org/dc/terms/identifier | "doi:10.1074/jbc.m809457200"xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Hasilik A."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Sandhoff K."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Breiden B."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Fluharty A.L."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Gieselmann V."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Schwarzmann G."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Yaghootfam A."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/author | "Matzner U."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/date | "2009"xsd:gYear |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/name | "J Biol Chem"xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/pages | "9372-9381"xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/title | "Saposin B-dependent reconstitution of arylsulfatase A activity in vitro and in cell culture models of metachromatic leukodystrophy."xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://purl.uniprot.org/core/volume | "284"xsd:string |
| http://purl.uniprot.org/citations/19224915 | http://www.w3.org/2004/02/skos/core#exactMatch | http://purl.uniprot.org/pubmed/19224915 |
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