General amino acid permease (GAP1) activity was evaluated in adenylate cyclase-deficient Saccharomyces cerevisiae to determine the effect of cAMP levels on GAP1 activity. Lowering cAMP concentrations in the culture media led to a decrease in the initial rates of L-citrulline uptake. Kinetics of the amino acid transport system showed a partial loss of transport capacity, with no apparent modifications in permease affinity.