Bass L, McNabb A
Department of Mathematics, University of Queensland, St Lucia, Brisbane, Australia.
J Theor Biol. 1988 Jul 21;133(2):185-91. doi: 10.1016/s0022-5193(88)80004-3.
We extend flux ratio theorems concerning ratios of unidirectional flux transients passed (in complementary experiments) through a medium of spatially inhomogeneous transport properties pertaining to diffusion, migration and temporary trapping of the transported substance. Any nonlinearity in the transport equations leads to a breakdown of the Ussing flux ratio theorem pertaining to all times. An integrated flux ratio theorem is proved for the case when the nonlinearity is in the kinetics of trapping, as when trapping sites can be saturated. The new theorem is shown to fail when the nonlinearity is due to a concentration-dependence of the diffusion coefficient, as in facilitated transport. The nature of a nonlinearity in membrane transport can therefore be elucidated experimentally by the use of the integrated flux ratio.
我们扩展了通量比定理，该定理涉及（在互补实验中）通过具有空间非均匀传输特性的介质（与所传输物质的扩散、迁移和暂时捕获有关）的单向通量瞬变之比。传输方程中的任何非线性都会导致在所有时间内与Ussing通量比定理相悖。当非线性存在于捕获动力学中时（如捕获位点可能饱和的情况），证明了一个积分通量比定理。结果表明，当非线性是由于扩散系数的浓度依赖性（如在易化传输中）时，新定理不成立。因此，通过使用积分通量比，可以通过实验阐明膜传输中非线性的性质。
