| Range |
~4X10^9 ions/cell/sec
|
| Organism |
Human Homo sapiens |
| Reference |
Gasbjerg PK, Knauf PA, Brahm J. Kinetics of bicarbonate transport in human red blood cell membranes at body temperature. J Gen Physiol. 1996 Dec108(6):565-75. p.571 right column 2nd paragraphPubMed ID8972394
|
| Primary Source |
Brahm,J. 1977. Temperature-dependent changes of chloride transport kinetics in human red cells.J. Gen. Physiol. 70: 283-306. & Wieth, J.O., and J. Brahm. 1985. Cellular anion exchange. In The Kidney: Physiology and Pathology. D.W. Seldin and G. Giebisch, editors. Raven Press, New York. 49-89.PubMed ID19556
|
| Method |
"On the basis of studies of chloride transport mainly at 0°C, the "ping-pong model" for anion exchange was proposed (Gunn and Frohlich, 1979 Frohlich and Gunn, 1986). According to this model, a transport site in the protein, unloaded or loaded with an anion, may either face the internal or the external compartment." |
| Comments |
"When the Arrhenius plots for Cl-, Br-, and F- were
fitted to two intersecting regression lines, the "break"
in the lines occurred at different temperatures for Cl-
(15°C) and Br- and F- (23-25°C), but at the same "critical"
turnover number of ~4×10^9 ions/cell/sec
(primary sources). The fact that
the break occurs at different temperatures for different
anions indicates that the nonlinear temperature dependence
is not related to a phase transition in the
membrane, which would occur at the same temperature
regardless of the anion substrate. If two straight
lines are used to fit the Arrhenius plot for HCO3- transport
(Fig. 3), they intersect around 13°C. Thus, for
monovalent anions, the break temperature ranges from
13 to 25°C, supporting the concept that the nonlinear
temperature dependence of anion transport is not related
to a phase transition in the membrane. The turnover
number for HCO3- transport at 13°C is ~4×10^9
ions/cell/sec, similar to the critical turnover number
for Cl-, Br-, and F-." |
| Entered by |
Uri M |
| ID |
110857 |