Beschreibung:
<jats:p>The nucleoside phosphotransferase from carrots forms <jats:italic>N</jats:italic>‐phosphorylhydroxylamine when substrates are hydrolysed in the presence of hydroxylamine. Denaturation of the enzyme after short incubation with the substrates leads to a protein, in which, after reduction with [<jats:sup>3</jats:sup>H]NaCNBH<jats:sub>3</jats:sub> and completer hydrolysis with 6 M HCl, labelled homoserine can be detected.</jats:p><jats:p>The first experiment provides evidence for an activated phosphorylenzyme, the second experiment shows that the intermediate is an acyl phosphate formed by a nucleophilic attack of an aspartate β‐carboxylate group.</jats:p>