INHIBITION STUDIES OF S-ADENOSYLHOMOCYSTEINE HYDROLASE PURIFIED FROM ACINETOBACTER-CALCOACETICUS ULA-501

Adenosine analogs previously reported as reversible inhibitors of mamm alian S-adenosylhomocysteine hydrolase (SAHase) have been found to exe rt similar effects on Acinetobacter calcoaceticus ULA-501 enzyme. In a ddition, two metal coordination compounds, cis-platinum diammine dichl oride (cis-DDP) and its trans isomer (trans-DDP), the former well know n for its employment in anticancer chemotherapy, were assayed on both bacterial and mammalian SAHases. In our conditions, trans-DDP appeared to be the strongest inhibitor toward both SAHases. Finally, treatment of the bacterial enzyme with a mixture of ATP-Mg acetate and KCl caus ed only a slight reversible inhibition, in contrast to the complete in activation exerted on the mammalian SAHase.