Linked Life Data

8922957

Source:http://linkedlifedata.com/resource/pubmed/id/8922957

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1997-2-18
pubmed:abstractText
The enzyme N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase (EC 3.1.4.45; uncovering enzyme) catalyzed the removal of N-acetylglucosamine from the N-acetylglucosamine-alpha-phospho-mannose portion of selected lysosomal enzyme oligosaccharide chains, thereby forming the mannose 6-phosphate signal which is responsible for the targeting of these lysosomal enzymes for transport into lysosomes. The uncovering enzyme has been purified approximately 7000-fold to electrophoretic homogeneity from Epstein-Barr virus-transformed human lymphoblast cells. The purification sequence involves solubilizing this membrane-bound enzyme with Tergitol NP-10, affinity chromatography on Lentil lectin-Sepharose 4B, ion-exchange chromatography on DEAE-Sephacel, chromatography on zinc(II)-IDA-Sepharose 6B, and preparative SDS-PAGE electrophoresis. The purified enzyme migrated as a single band of 114 kDa which was coincident with enzyme activity on analytical SDS-PAGE electrophoresis. Characterization studies of the purified enzyme demonstrated that catalytic activity was maximal at pH 6.95 and that the enzyme retained full activity following incubation for 10 min at 60 degrees C. No requirement was found for a divalent cation, but Zn2+, Hg2+, and Cu2+ were found to reduce the enzyme's activity by 30-40%. The highest catalytic efficiency was observed with N-acetylglucosamine-phospho-methylmannoside as a substrate while uridine diphosphate-N-acetylglucosamine, N-acetylglucosamine-phosphomannose-uteroferrin, and N-acetylglucosamine-phosphate were also cleaved by the enzyme with decreasing efficiency. Acetamino-deoxycastanospermine was a potent inhibitor of the human enzyme with a Ki of 0.35 microM, while N-acetylglucosamine phosphate (Ki 1.58 mM) and N-acetylglucosamine (Ki 5.1 mM) inhibited the enzyme to a lesser degree.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0959-6658
pubmed:author
pubmed:issnType
Print
pubmed:volume
6
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
619-26
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Purification and characterization of human lymphoblast N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase.
pubmed:affiliation
Department of Neurosciences 0624, University of California, San Diego, La Jolla 92093-0624, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.