How membrane carriers function: the critical contribution of W.F. Widdas (1952) to modern understanding

This paper reviews the contribution to the field of transport biology of W.F. Widdas' paper 'Inability of diffusion to account for placental glucose transfer in the sheep and consideration of the kinetics of a possible carrier transfer' published in the Journal of Physiology in 1952. The importance of this mathematical analysis, and of its assumptions and predictions, has been supported in a number of subsequent publications over the last half century. But its vindication emerges specifically from the recent successful solution of the three dimensional structure of a membrane transport protein, the sugar carrier lac permease. Predictions arising from the 1952 paper are confirmed by this very recent study. Reasons for the relatively slow acceptance of the Widdas carrier hypothesis and its implications are discussed.