ACTIVITY OF ALKALINE-PHOSPHATASE BOUND TO POLYSULFONE MEMBRANES

As part of the on-line radiosynthesis of radiopharmaceuticals labeled with short-lived positron emitters, the dephosphorylation of an appropriate nucleotide to the corresponding nucleoside is required. The rapid dephosphorylation of thymidine monophosphate was accomplished using the enzyme alkaline phosphatase, which was covalently bound to a derivatized polysulfone membrane through a phthalate or succinyl linkage. A nearly quantitative conversion of thymidine was accomplished within a 2-3 minute period making this system amenable for use with carbon-11 (half-life = 20.4 minutes) labeled nucleotides.