GDP + ATP <=> guanosine 3',5'-bis(diphosphate) + AMP
gdp + atp <=> guanosine 3',5'-bis(diphosphate) + amp
GDP + ATP <=> guanosine 3',5'-bis(diphosphate) + AMP
gdp + atp <=> guanosine 3',5'-bis(diphosphate) + amp