TABLE 3.

Inhibition of glucose PEP-dependent phosphorylation by various sugars^a

Inhibitor sugar	Glucose PTS activity (nmol/mg/min ± SE)b	% Inhibition
None	5.96 ± 1.03	0
Galactose	5.77 ± 0.10	3.18
Fructose	5.81 ± 0.45	2.51
2-DG	4.46 ± 0.56	25.16
Mannose	3.52 ± 0.43	40.94

^aA total of 400 μg of membrane proteins, 2 mM PEP, 1 μg of His₆-EI, 100 μg of His₆-HPr, 1 to 10 μg of His₆-IIAB^Man, 10 mM ¹⁴C-labeled sugar (0.1 μCi/μmol), and 200 mM unlabeled sugar were mixed together and incubated for 20 min at 37°C.

^bThe activities are expressed as nanomoles of phosphorylated product per milligram of membrane protein per minute. Results are from at least two independent experiments.