EXTRACELLULAR ASCORBATE STABILIZATION - ENZYMATIC OR CHEMICAL PROCESS

Ascorbate is stabilized in the presence of HL-60 cells. This stabiliza tion has been questioned as a simple chemical effect. Further properti es and controls about the enzymatic nature of this stabilization are d escribed and discussed. Our results showed that cAMP derivatives and c AMP-increasing agents stimulated the ability of HL-60 cells to stabili ze ascorbate. On the other hand, tunicamycin, a glycosylation-interfer ing agent, inhibited this ability. These data, together with hormonal regulation, support the hypothesis of an enzymatic redox system locate d at the plasma membrane as being responsible for the extracellular as corbate stabilization by HL-60 cells.