Preparation of Crystalline Nucleoside Diphosphate Kinase from Baker's Yeast and Identification of 1‐[³²P]Phosphohistidine as the Main Phosphorylated Product of an Alkaline Hydrolysate of Enzyme Incubated with Adenosine [³²P]Triphosphate

A nucleoside diphosphate kinase has been highly purified from baker's yeast, and has been obtained in a crystalline form from an ethanol‐containing medium. During short‐time incubation with [ 32 P]ATP, the enzyme was phosphorylated to an extent of about 3–4 phosphoryl groups per mole of enzyme assuming a molecular weight of 10 5 . This indicates an intermediate phosphorylation of the enzyme. 1‐[ 32 P]Phosphohistidine was shown to be the dominating radioactive degradation product in an alkaline hydrolysate of the 32 P‐labelled enzyme. In addition, 3‐[ 32 P]‐phosphohistidine and N e ‐[ 32 P]phospholysine were obtained in small amounts. The results indicate that the amino acid sequence around the reactive 1‐phosphohistidine of the yeast enzyme is different from that of human erythrocytic and bovine liver nucleoside diphosphate kinase.