p. 223 - 237 DETERMINATION OF SOME NATURAL INHIBITORS OF PEPSIN, TRYPSIN AND CHYMOTRYPSIN IN SEVERAL INVERTEBRATE AND FISH SPECIES ALONG THE ROMANIAN COAST OF THE BLACK SEA Natalia Rosoiu 1)Mihai Serban 2) and Maria Panait 1) 1) Romanian Marine Research Institute Constanta 2) Faculty of Veterinary Medicine Bucharest Abstract The paper is presenting preliminary data on some natural inhibitors of pepsin, trypsin and chymotrypsin in the protein extracts from Actinia aequinia, Rapana thomasiana, Squalus acanthias, Odontogadus merlangus euxinus and Engraulis encrassicholus poticus.