. 2015 Dec 8;291(6):2837–2847. doi: 10.1074/jbc.M115.690156

TABLE 1.

Antibiotic association (k_on) and dissociation (k_off) rate constants at low salt concentration

From single channel measurements for OmpC20 and OmpC33, conditions were: 200 mm KCl, 20 mm MES, pH 6, k_on = ({No. of events/s}/3 × [c]), k_off = (1/residence time), the flux J = (k_on /2) × Δc with Δc = 2.5 mm. k_on^cis is calculated from −100 mV (for cis addition) and k_on^trans is calculated from +100 mV (for trans addition).

Antibiotics	Porin	k_on^cis (10³)	k_on^trans (10³)	k_off	J
		m⁻¹ s⁻¹		s⁻¹	molecules/s
Imipenem	OmpC20	96 ± 16	6^a	23,000	120 ± 20
Imipenem	OmpC33	2.8 ± 0.2	7	16,000	3.5
Meropenem	OmpC20	35 ± 0.6	No effect resolved	20,000	43
Meropenem	OmpC33	29 ± 3	No effect resolved	20,000	36

^a Calculated from −100 mV.