TABLE 2.

In vitro PEP-dependent phosphorylation of various sugars^a

Addition to the reaction mixture	PTS activity (nmol/mg/min)b for:
	Glucose	Mannose	2-DG	Fructose	Galactose
Membd + PEP	0.15	NDc	0.35	ND	ND
Memb + PEP + EI + IIABMan	0.60	ND	ND	ND	ND
Memb + EI + HPr + IIABMan	0.24	ND	ND	ND	ND
Memb + PEP + EI + HPr	5.44	4.87	3.11	1.85	0.38
Memb + PEP + EI + HPr + IIABMan (1 μg)	5.96	ND	ND	ND	ND
Memb + PEP + EI + HPr + IIABMan (5 μg)	9.33	ND	ND	ND	ND
Memb + PEP + EI + HPr + IIABMan (10 μg)	11.32	8.89	4.93	2.38	0.14

^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, and 10 mM ¹⁴C-labeled sugar (0.1 μCi/μmol) 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. The standard errors are less than 17%.

^cND, not determined.

^dMemb, membrane.