Extracellular ascorbate stabilization: enzymatic or chemical process?
Ascorbate is stabilized in the presence of HL-60 cells. This stabilization has been questioned as a simple chemical effect. Further properties and controls about the enzymatic nature of this stabilization are described and discussed. Our results showed that cAMP derivatives and cAMP-increasing agents stimulated the ability of HL-60 cells to stabilize ascorbate. On the other hand, tunicamycin, a glycosylation-interfering agent, inhibited this ability. These data, together with hormonal regulation, support the hypothesis of an enzymatic redox system located at the plasma membrane as being responsible for the extracellular ascorbate stabilization by HL-60 cells.
Departamento de Biología Celular, Facultad de Ciencias, Universidad de Córdoba, Spain.
J C
JC
Rodríguez-Aguilera
P
P
Navas
D001204:Ascorbate Oxidase / Q000378:metabolism; D001205:Ascorbic Acid / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D002614:Chelating Agents / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D005110:Extracellular Space / Q000378:metabolism*; D005609:Free Radicals; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism; D010084:Oxidation-Reduction; D013696:Temperature; D014407:Tumor Cells, Cultured
D002614:Chelating Agents; D005609:Free Radicals; D009363:Neoplasm Proteins; D000242:Cyclic AMP; D001204:Ascorbate Oxidase; D009247:NADH, NADPH Oxidoreductases; C023927:monodehydroascorbate reductase (NADH); D001205:Ascorbic Acid