Phosphoryl transfer reaction regulated by amino acid side chains: a model for phosphoproteins.

ABSTRACT

Through a kinetic study of the reaction of phosphoamino acids as incubated in alcohol, it was found that the inter- and intramolecular phosphoryl transfer reactions were regiospecific and stereoselective. First, the phosphoryl transfer reaction required the regio-specifically neighboring alpha-carboxy group activation of amino acid but not beta-carboxy group. The intramolecular side chain catalytic effects relative to hydrogen for N-phosphoamino acids compared to N-phosphoglycine were a 119-to 4-times enhancement of the phosphoryl transfer reaction, respectively. Secondly, the intramolecular N-->O phosphoryl transfer migration was highly stereoselective, since the reaction rate constant of phosphoallothreonine relative to its diastereomeric threonine was reduced to half. The pentacoordinate transition states modulated by the amino acid side chains were demonstrated by the formation rates of intramolecular pentacoordinate spiro mixed anhydride compounds.