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DIVALENT CATION‐ACTIVATED ECTO‐NUCLEOSIDE TRIPHOSPHATASE ACTIVITY OF NERVOUS SYSTEM CELLS IN TISSUE CULTURE
Author(s) -
Stefanovic V.,
Léadig M.,
Mandel P.
Publication year - 1976
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1976.tb10411.x
Subject(s) - divalent , nucleoside , extracellular , enzyme , nucleoside triphosphate , biochemistry , chemistry , membrane , intracellular , substrate (aquarium) , nucleotide , biology , ecology , organic chemistry , gene
— Intact neuroblastoma and glial cells in monolayer culture hydrolysed ATP added to their medium. Evidence is presented that ATP is cleaved outside of the permeability barrier of the plasma membrane and the product is liberated in the extracellular medium, i.e. the enzyme is an ecto‐enzyme. Divalent cations such as Mg 2+ , Ca 2+ , Mn 2+ and Co 2+ activate the enzyme. In neuroblastoma cells, Ca 2+ is the preferential cation for activation; Mg 2+ in glial cells. Substrate specificity was very low when different nucleoside‐5′‐triphosphates were examined. Competition studies have revealed that all of the nucleoside triphosphates are hydrolysed by the same enzyme: divalent cation‐activated ecto‐nucleoside‐5′‐triphosphate phosphohydrolase. Developmental pattern of the enzyme in several lines was established. The role of enzyme in the transport of divalent cations across the plasma membrane and/or in the physical properties of the membrane is suggested.