An investigation into the catalytic deuteration and tritiation of dehydroproline9-buserelin

For optimizing the catalytic tritiation of peptides, the catalytic deuteration of buserelin and DhP9-buserelin1 in DMA (dimethylacetamide) and D2O was studied by FAB-MS. The deuteration degrees achieved after reaction of DhP9-buserelin were comparable in both solvents. The nonspecific incorporation of deuterium found after deuteration of buserelin was clearly lower after reaction in DMA. Tritiation of DhP9-buserelin in DMA using 85% tritium gas, with conditions optimized by the deuteration experiments, resulted in a specific radioactivity of 1.3 TBq/mmol. 72 and 13 percent of the incorporated radioactivity were found to be associated with proline and histidine, respectively, after acidic hydrolysis. (Author)