title: Stopped flow kinetic studies of adenosine triphosphate phosphoribosyl transferase, the first enzyme in the histidine biosynthesis of Escherichia coli.
abstract: 1. Stopped flow kinetic studies of ATP phosphoribosyl transferase (EC 2.4.2.17) from Escherichia coli showed that high protein concentration and elevated temperature do not give a drastic reduction of the transferase activity when measured before inhibitory amounts of PRibATP (product) has accumulated. 2. A small and slow increase in activity follows a reduction of the protein concentration showing a slow dissociation of the enzyme from an inactive to an active species. 3. By lowering the concentration of the inhibitor histidine, a fairly slow increase in activity is observed indicating a dissociation of the enzyme. 4. AMP and histidine together give a strong inhibition of the activity, while AMP alone stimulates the enzyme activity.
mesh_terms: D001276:ATP Phosphoribosyltransferase / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D006639:Histidine / Q000096:biosynthesis* / Q000494:pharmacology; D007700:Kinetics; D010430:Pentosyltransferases / Q000378:metabolism*
chemical_list: D000249:Adenosine Monophosphate; D006639:Histidine; D010430:Pentosyltransferases; D001276:ATP Phosphoribosyltransferase