Transport of 3-o-Methylglucose Into and Out of Storage Cells of Daucus carota

摘要: The movement of labeled 3-o-methylglucose (MeG) into and out thin carrot discs has been followed in order to gain information on sugar entry exit mechanisms. Little or no metabolism this derivative appears occur the tissue, since products were detected either by chromatography analysis respiratory CO(2).The curve relating external concentration deviated somewhat from a rectangular hyperbola but suggested carrier mechanism. Glucose MeG each competitively inhibited uptake other. K(i) for was estimated be 3 times K(m) its uptake.When incubated transferred H(2)O, lost solution Free Space re-absorbed against 7-fold gradient.The addition unlabeled glucose medium surrounding which had maintaining ratio internal 75:1 brought about release stored isotope. This probably not due exchange diffusion stricto sensu.Efflux previously absorbed isotopic containing temperature-sensitive. kinetics efflux complex did suggest simple process related overall content. However there is evidence (including falling rate with time) that slow (or adsorption) contributed substantially efflux. source flow appeared neither readily accessible nor main storage compartment. Calculation indicated volume "slow compartment" might 1% total discs.