When immobilized yeast was exposed to nutrients, the resulting heat effect (dQ/dt; J sec^-1) increased exponentially with a doubling time (t₂) of 2.2±0.3hr. The half life (dQ/dt) under non-growing conditions with sucrose as substrate was 84hr. The kinetics of the transformation of a series of sugars were characterised. The Michaelis constant (K_m) and maximal heat effect, (dQ/dt)_max, were determined using two common enzyme kinetics linearization plots. The shapes of the Eadie plots for some sugars are discussed in terms of currently proposed mechanisms of their uptake.