The use of the logarithmic transformation in the calculation of the transport parameters of a system that obeys Michaelis-Menten kinetics.

1. A logarithmic method is described for the calculation of the transport parameters, K(m) and V(max.)' of a biological system obeying Michaelis-Menten kinetics. 2. This logarithmic method leads to a way of estimating the transport parameters that has not apparently been used previously. It allows the separation of variance due to V(max.) from other variance, and so reduces the fiducial limits that can be placed on an estimation of K(m). 3. The results of studies on the transport of l-histidine and l-monoiodohistidine by rat intestinal sacs in vitro have been used to illustrate the application of the new method. Estimates of the transport parameters have also been made by two alternative procedures. The relative merits of the three methods are discussed.