Abstract
Polynucleotide kinase (bacteriophage-T4-infected E. coli B) catalyzes the transfer of the [.gamma.-16O,17O,18O]phosphoryl group from 5''-[.gamma.(S)-16O,17O,18O]ATP to 3''-AMP with inversion of configuration at the P atom. The simplest interpretation of this observation is that the [.gamma.-16O,17O,18O]phosphoryl group is transferred directly from ATP to the co-substrate by an in-line mechanism.