| Range |
Table - link
|
| Organism |
Bacteria Escherichia coli |
| Reference |
Dornmair K, Overath P, Jähnig F. Fast measurement of galactoside transport by lactose permease. J Biol Chem. 1989 Jan 5 264(1):342-6.PubMed ID2642475
|
| Primary Source |
Wright JK, Overath P. Purification of the lactose:H+ carrier of Escherichia coli and characterization of galactoside binding and transport. Eur J Biochem. 1984 Feb 1 138(3):497-508.PubMed ID6363073
|
| Method |
Lactose permease of Escherichia coli was reconstituted
into vesicles of dimyristoylphosphatidylcholine (DMPC),
and the rate of galactoside counterflow was measured
in the millisecond time range: The problem of measuring true
initial rates in vesicles is of general relevance, because recently (as of 1989)
a number of transport proteins has been isolated and reconstituted into lipid vesicles. The idea was to measure transport
in vesicles faster than done conventionally and thus to compensate
for their small size. Researchers, therefore, employed a rapid
filtration technique which permitted them to observe galactoside
transport in the time range of tens of milliseconds, i.e. 2 or 3
orders of magnitude faster than with conventional filtration
techniques. Furthermore, they measured transport in the so called
counterflow mode by detecting the influx of a labeled
substrate into vesicles loaded with another, unlabeled substrate. The imported substrate is transiently accumulated
in the vesicles, because the export route is occupied by the
other substrate. This means that influx occurs over an extended
period of time with the true initial rate. |
| Comments |
In all cases, the internal melibiose concentration was 15 mM, pH
7.6, and the temperature was 20 °C. Data from first 4 samples in table link from primary source. See BNID 103159,104098,104176 |
| Entered by |
Uri M |
| ID |
105064 |