EFFECTS OF DIPEPTIDES CONTAINING THE AMINO-ACID, PROLINE ON THE CHEMOTAXIS OF TETRAHYMENA-PYRIFORMIS - EVOLUTIONARY CONCLUSIONS ON THE FORMATION OF HORMONE RECEPTORS AND HORMONES

Our investigations demonstrate that proline-containing dipeptides can provoke a chemosensory response from the unicellular Tetrahymena pyrif ormis. The chernotactic effects of the dipeptides have a close relatio nship with the side chain and the lipophilicity of the amino-terminal amino acid. Comparison of 'mirror' variants of proline-containing dipe ptides points to the fact that dipeptides with small side chain and no n-polar character amino acids (Gly-Pro, Ala-Pro) are preferred on the amino-terminal end. In the case of amino acids with very variable side chains, small (Pro-Gly) and the large side chain and non-polar charac ter amino acids (Pro-Leu, Pro-Phe) on the carboxyl-terminal end can in duce significant chemotactic responses. With valine on any terminus th e proline-containing dipeptide induced a weak repellent effect. (C) 19 97 Academic Press Limited.