The bacterial phosphotransferase system: Kinetic characterization of the glucose, mannitol, glucitol, and N-acetylglucosamine systems

✍ Scribed by Frank C. Grenier; E. Bruce Waygood; Milton H. Saier Jr.

• Book ID: 102879738
• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 500 KB
• Volume: 31
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240310203

✦ Synopsis

The kinetic mechanisms by which the glucose, glucitol, N-acetylglucosamine, and mannitol enzymes I1 catalyze sugar phosphorylation have been investigated in vitro. Lineweaver-Burk analyses indicate that the glucose and glucitol enzymes I1 catalyze sugar phosphorylation by a sequential mechanism when the two substrates are phospho-enzyme ILI and sugar. The N-acetylglucosamine and mannitol enzymes 11, which do not function with an enzyme 111, catalyze sugar phosphorylation by a ping-pong mechanism when the two substrates are phospho-HPr and sugar. These results, as well as previously published kinetic characterizations, suggest a common kinetic mechanism for all enzymes I1 of the system. It is suggested that all enzymes I1 and enzyme 11-111 pairs arose from a single (fused) gene product containing two sites of phosphorylation and that phosphoryl transfer from the second phosphorylation site to sugar can only occur when the enzyme 11-III pair is present in the associated state.