Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1992-4-23
pubmed:abstractText
The dependence of constitutively expressed tyrosinase (dopa oxidase) activity on glycosylation in lightly pigmented human melanoma cells (MM96E) was determined using tunicamycin (TM), which prevents transfer of oligosaccharide chains to nascent protein (core glycosylation), the glucosidase inhibitors castanospermine (CS) and deoxynojirimycin (dNM), and the mannosidase inhibitors deoxymannojirimycin (dMM) and swainsonine (SW). TM caused irreversible inhibition of tyrosinase activity and carbohydrate synthesis as judged by incorporation of 3H-fucose. Tyrosinase in CS- and dNM-treated cells showed 50% loss of activity within 5 h but recovered rapidly when the drugs were removed; dMN and SW had little effect. Expression of the tyrosinase 2B7 epitope and of an 80-kDa melanosomal antigen (B8G3) was inhibited by TM but not by CS, dNM, dMM, or SW. CS and dNM appeared to decrease the half-life of active tyrosinase. Overall, these results indicate that 1) in addition to the requirement for core glycosylation the removal of glucose residues plays a critical role in the formation of active human tyrosinase; 2) glucosidase inhibitors appear to cause an accumulation of inactive tyrosinase and increase the degradation rate of active enzyme; and 3) later stages in oligosaccharide processing are not required for maintaining tyrosinase activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0022-202X
pubmed:author
pubmed:issnType
Print
pubmed:volume
98
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
481-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:1532183-1-Deoxynojirimycin, pubmed-meshheading:1532183-Antibodies, Monoclonal, pubmed-meshheading:1532183-Antigens, pubmed-meshheading:1532183-Blotting, Western, pubmed-meshheading:1532183-Cell Survival, pubmed-meshheading:1532183-Chromatography, Affinity, pubmed-meshheading:1532183-Flow Cytometry, pubmed-meshheading:1532183-Glucosamine, pubmed-meshheading:1532183-Glucosidases, pubmed-meshheading:1532183-Humans, pubmed-meshheading:1532183-Indolizines, pubmed-meshheading:1532183-Melanocytes, pubmed-meshheading:1532183-Melanoma, Experimental, pubmed-meshheading:1532183-Methionine, pubmed-meshheading:1532183-Monophenol Monooxygenase, pubmed-meshheading:1532183-Skin Neoplasms, pubmed-meshheading:1532183-Subcellular Fractions, pubmed-meshheading:1532183-Sulfur Radioisotopes, pubmed-meshheading:1532183-Tumor Cells, Cultured
pubmed:year
1992
pubmed:articleTitle
Rapid and reversible inhibition of tyrosinase activity by glucosidase inhibitors in human melanoma cells.
pubmed:affiliation
Queensland Institute of Medical Research, Brisbane, Australia.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't