A general amino-acid permease is inducible in Chlorella vulgaris

Glucose or non-metabolizable glucose analogues induce two systems of amino-acid transport in Chlorella vulgaris: an arginine-lysine system and a proline system. An additional third system of amino-acid transport is induced when glucose and an inorganic nitrogen source are present during glucose induction. The transport rates in glucose-NH 4 (+) -treated cells are 10 to 80 times higher than in untreated cells. The transport system shows a rather broad specificity and catalyses the transport of at least ten neutral and acidic amino acids. Three of these amino acids (L-alanine, L-serine and glycine) are transported by the proline system as well. The system is specific for L-amino acids and has a pH optimum between 5 and 6. Transport by this system seems to be active, since amino acids are accumulated inside the cells.