Glyceraldehyde‐3‐phosphate activates auto‐ADP‐ribosylation of glyceraldehyde‐3‐phosphate dehydrogenase

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Abstract
Nitric oxide was recently demonstrated to stimulate ADP‐ribosylation of glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH). Our studies on the effect of glyceraldehyde‐3‐phosphate (GA3P), the natural substrate of dehydrogenase activity of GAPDH, indicated GA3P to be another very potent activator of ADP‐ribosylation of the enzyme. GA3P was able to activate ADP‐ribosylation only in the presence of DTT. The action of GA3P was associated with inhibition of GAPDH dehydrogenase activity. K a for GA3P was at least 50‐fold lower and maximal activation was somewhat higher than these values for other aldehydes that were also able to enhance GAPDH ADP‐ribosylation in the presence of DTT. ADP‐ribosylation was blocked by carboxamidomethylation of the essential cysteine SH‐group. The bond between the prelabeled protein and ADP‐ribose was resistant to hydrolysis with hydroxylamine and HgCl2, suggesting that a lysine ε‐amino group is the target for ADP‐ribosylation.