The pH dependence of exchange transport of glucose in human erythrocytes

Publisher Website
Google Scholar
Abstract
In glucose exchange transport into red blood cells the rate of glucose uptake showed two pH dependent maxima, with the larger at approximately pH 7.5 and the smaller one at pH 3.In the studied pH range the relation between the rate of glucose uptake and the substrate concentration followed Michaelis‐Menten kinetics. While the maximal velocity (V) reflected the pH changes of the media, the Michaelis constant (Km) remained constant.The dissociation constants of the groups of the free carrier and the carrier‐glucose complex were the same. The pK of the acidic group was 5.2 and of the basic group 9.5.Glucose was not bound to groups of the carrier which dissociated protons in the pH range of three to nine.By rearranging the equation for the pH dependence of the relative influx a more definitive graphic determination of the pK values was produced.