Hydroxylamine kinase

Coon and co-workers ttt-ltJia) discovered and crystallized an enzyme Itia) named hydroxylamine kinase that degrades ATP in the presence of bicarbonate and hydroxylamine. It was believed that adenylic acid and pyrophosphate were products of this reaction and it was considered that this enzyme participated in the carboxylation reaction in leucine catabolism by activating COi. Active CO was presumed to be adenyl-COj. Later this enzyme was found not to participate in the carboxylation reactions. More recently Kupiecki and Coon lt4b) established that hydroxylamine kinase is very probably identical with pyruvic kinase and fluoro kinase of Tietz and Ochoa (96). Interesting differences were found in the activation of the different enzyme functions by metal ions. Zn, but not Mg++, promoted hydroxylamine kinase activity, whereas Mg, but not Zn promoted iluorokinase and pyruvic kinase activity. 

The evidence supporting the double-displacement mechanism for phosphoglycerate kinase was less extensive than that advanced for the acetate kinase reaction. The strongest evidence was the formation of a [ P]phosphoenzyme by reaction of the purified enzyme with either [y- PlATP or 1,3,[l- P]diphosphoglycerate. The P was removed from the enzyme by incubation with 3-phosphoglycerate or ADP. Reaction of the P-labeled phosphoenzyme with hydroxylamine also... 

The aspartate kinase reaction is not dependent upon the presence of hydroxylamine during the assay, only at the end of the assay for the development of the color complex (Davies and Miflin, 1977). 

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