Isolation of 3-phosphohistidine from phosphorylated pyruvate, phosphate dikinase.

Abstract
Pyruvate, phosphate dikinase (EC 2.7.9.1) catalyzes formation of phosphoenolpyruvate, AMP and PPi from pyruvate, ATP and Pi. A pyrophosphoryl and phosphoryl form of the enzyme is involved in this transfer. The [32P]phosphoryl form of pyruvate, phosphate dikinase was prepared with enzyme isolated from Bacteroides symbiosus. The [32P]phosphoryl enzyme had properties corresponding to a phosphoramidate linkage, and this was confirmed by isolation of 3-[32P]phosphohistidine from alkaline hydrolysates of the enzyme. The histidyl residue is considered to be the pyrophosphoryl- and phosphoryl-carrier between the 3 substrate sites of this enzyme.