THE STEREO-SPECIFICITY AND TEMPERATURE-DEPENDENCE OF THE PERMEABILITY OF HUMAN ERYTHROCYTES TO ALDOSES

¹ Department of Biochemistry, Edinburgh University Medical School, Teviot Place, Edinburgh EH8 9AG

Time-courses have been determined between 2·0°C and 25·5°C for the uptake of D(+) glucose, D(+) xylose and L(+) arabinose by human erythrocytes. They can be explained by assuming uptake is governed by a mobile carrier of the Widdas type. Since at any temperature the three aldoses have the same maximum rate of permeation but different half-saturation concentrations for the carrier, it is argued that they have a common carrier, and that the rate-limiting step in permeation is the translocation across the membrane of the carrier or carrier-aldose complex. Data are also given which suggest that - and -glucose have different half-saturation concentrations for the carrier.

Note:

We are grateful to Miss F. C. Wilkinson and Mrs M. Ryan for their skilled technical assistance.

We wish to thank the Edinburgh and South-East Scotland Blood Transfusion Service for their co-operation.