Table II. Diffusion rate of sugars through the OmpL channel.

Sugar	Specific activitya
Glucose	81 ± 10
Arabinose	70 ± 18
Galactose	76 ± 7
N-acetyl glucosamine	12 ± 3
Maltose	2 ± 1
Sucrose	2 ± 1
Stachyose	0
Gly (4) peptide	148 ± 21

Purified OmpL protein (1 µg) was reconstituted with 2.4 µmol of phosphatidylcholine and 0.2 µmol of diacetylphosphate and resuspended in 300 µl of 15% Dextran T-40. Seventeen microlitres of proteoliposome suspension were diluted into 0.6 ml of an iso-osmotic solution of sugar. The complete details of the proteoliposome construction are as described previously (Nikaido et al., 1991). The initial rate of decrease of optical density was measured.

^aOD change ×1000/min. The standard deviation is from four experiments carried out under identical conditions.