Cross-reacting material to monoclonal anti-G6PD in the absence of catalytic activity.

Monoclonal antibody prepared against highly purified rat liver G6PD was used to probe the mode of regulation of this enzyme in a mammalian model system. Material cross-reacting with antibody against liver G6PD was found in similar amounts in extracts of two genetically related rat hepatoma cell lines, only one of which exhibits detectable enzymatic activity when both are cultured under identical conditions in vitro. The data suggest a post-translational event is necessary for the expression of catalytic activity for G6PD in this model system.