Patterns of uptake of dissolved amino acids in mussels (Mytilus edulis)

Uptake of dissolved amino acids was measured in mussels (M. edulis ) adapted to 50% artificial sea water or to the sea water containing 2 mM glycine. In mussels adapted to amino-acid free sea water net uptake from mu molar solutions of glycine, glutamic acid, taurine, glutamine and tyrosine could be described by the Michaelis-Menten equation. Mussels adapted to 2 mM glycine exhibited more complex patterns of uptake that changed with time after transfer to mu molar solution of glycine. It is suggested that the properties of the epidermal transport systems are adaptable, and that they are modified by the presence of amino acids in the medium, perhaps indirectly through changes in the concentrations of the intracellular pool of free amino acids. The uptake sea water express the maximum capacities for net uptake.