Enzymatic phosphoryl-transfer reactions, chiral

Enzymatic phosphoryl transfer reactions are ubiquitous in nature and play significant roles in ATP hydrolysis and protein phosphorylation processess. As previously described, pentacoordinate phosphorus species have been assumed as transient intermediates or transition states in these pathways and their structural and electronic properties are undoubtedly related to the outcome of the process. Therefore, to aid understanding of the phosphorus-catalyzed biological routes, many model pentacoordinated phosphoranes have been synthesized. While most studies have focused on aspects of apicophilicity, anti-apicophilicity or Berry pseudorotation, there have been limited investigations on the stereochemistry of pentacoordinated spirophosphoranes with a chiral phosphorus atom. In the past year, much attention has been paid to the synthesis and determination of absolute configuration of several chiral pentacoordinate spirophosphoranes derived from D- and L-aminoacids. Some significant achievements in this area will be discussed in this section. 

Use of Chiral [ < 0, 0,i 0]Phosphate Esters to Determine the Stereochemical Course of Enzymatic Phosphoryl Transfer Reactions... 

Fig. 17 The two typical reaction mechanisms employed by phosphatases. In (a), the phos-phoryl group is transferred directly to a water molecule, which is typically bound to one or two metal ions if the substrate is made chiral at phosphorus, the stereochemical outcome is inversion. In (b), the phosphoryl group is first transferred to an enzymatic residue. In a subsequent step the phosphoenzyme intermediate is hydrolyzed. Since each step occurs with inversion of configuration at phosphorus, the net outcome is retention. Pi inorganic phosphate.

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