Kinetic parameters for amino acid transport under various conditions

Range Table - link
Organism Bacteria Escherichia coli
Reference Robertson DE, Kaczorowski GJ, Garcia ML, Kaback HR. Active transport in membrane vesicles from Escherichia coli: the electrochemical proton gradient alters the distribution of the lac carrier between two different kinetic states. Biochemistry. 1980 Dec 9 19(25):5692-702. p.5698 table IIPubMed ID7006690
Comments P.5694 left column 2nd paragraph: "Results: ΔµH+ and the Effects of Valinomycin and Nigericin: Since many of the kinetic studies presented below (Figures 1, 6-9 Table II) were carried out under conditions where ΔµH+ and its components were varied systematically in a single preparation of membrane vesicles, a few points regarding these parameters are noteworthy (Table I BNID 112480)." P.5698 left column 2nd paragraph: "One puzzling but possibly important point is that the transport of serine and threonine, which presumably share the same transport system, is affected by variations in Δѱ, ΔpH, and external pH in different ways (Table II). The Vmax for serine transport at pH 5.5 appears to be more dependent upon ΔpH, while that for threonine transport is more dependent upon Δѱ. Even more puzzling is the observation that the Vmax for serine transport is increased by 55% at pH 7.5, while that for threonine is decreased by 59%. Perhaps these variations may be related to the difference in PI'S of these amino acids (6.53 for threonine vs. 5.68 for serine)." See notes beneath table
Entered by Uri M
ID 112481