THE DIFFERENT CHEMICAL PROPERTIES OF TWO PHOSPHORYL GROUPS IN Nα, Nε-BIS(O,O-DIISOPROPYL) PHOSPHOLYSINE

Abstract

The reactivities of Nα, Nε-bis(O,O-diisopropyl) phospholysine ((DiPP)₂lys) 1 in Tris-HCl buffer and n-butanol were investigated. The Nα phosphoryl group was liable to be cleaved from the lysine in pH 7.5 Tris-HCl buffer, which was observed to be a first-order kinetic reaction with k=2.95 × 10⁻⁵ sec⁻¹; however, the Nε phosphoryl group was very stable. The ester groups of the Nα phosphoryl group could be exchanged by the n-butanol, which was also a first-order kinetics reaction with k=2.3 × 10⁻⁵ sec⁻¹; but to Nε phosphoryl group, no ester exchange reaction occurred. The neighboring carboxyl group participation leading to the formation of penta-coordinate phosphorus transition state was suggested.

Key Words:

• Nα
• Nε-bis(O,O-diisopropyl)phospholysine
• hydrolysis
• ester exchange
• carboxyl group participation
• penta-coordinate transition state