Ab Initio and MNDO Calculation of the Intermediates of N-Diisopropylphosphoryl L-lspartic Acid

Many biological processes are regulated by the phosphorylation and dephosphorylation of amino acid residues in the proteins^1]. High-coordinate phosphorus intermediates forming from amino acid residues in protein are of great importance in the process of phosphorylation and dephosphorylation of protein. It has been proposed that the mechanisms of phosphorylation through penta-coordinate intramolecular mixed carboxylic-phosphoric anhydride intermediates^2]. It was found that α-COOH group^3] and β-COOH group^4] in aspartic acid had different activities in the ester exchange on phosphorus. So it is important to discuss which carboxylic acids is involved in the penta-coordinate phosphorus intermediate of aspartic acid.