Stereochemical Course of a Phosphokinase Using a Chiral [¹⁸O]Phosphorothioate. Comparison with the Transfer of a Chiral [¹⁶O,¹⁷O,¹⁸O]Phosphoryl Group

Synthetic adenosine 5ʹ-O-[3-¹⁸O, 3-thio]tri-phosphate having the R configuration at the γ-phosphorus has been used as a substrate in the reaction catalyzed by glycerol kinase. The product sn-glycerol 3-[¹⁸O]phosphorothioate has been isolated, and the configuration at phosphorus has been determined by ring closure to the two diastereoisomeric cyclic 2, 3-phosphorothioates of sn-glycerol and analysis of the ¹⁸O content of each diastereoisomer. The structural identity of these diastereoisomers has been determined by correlation with one of the corresponding diastereoisomers of the cyclic 2, 3-phosphorothioate of D-glycerate, whose crystal structure is reported here. From these experiments it is evident that glycerol kinase catalyzes the transfer of a thiophosphoryl group with inversion of the configuration at phosphorus, in gratifying agreement with the result from the transfer of a chiral [¹⁶O,¹⁷O,¹⁸O]phosphoryl group [Blättler, W.A., & Knowles, J.R. (1979) J. Am. Chem. Soc. 101, 510].