Dr. Murai Éva szerk.: Parasitologia Hungarica 14. (Budapest, 1982)

The inhibitor was obtained in a partially purified form by means of affinity chromatography, and its properties were studied. Until now such a detailed study has not been made on the inhibitors of trematodes. The isolation and purification, which consisted of several steps with previous procedures, by the use of affinity chromatography have been simplified giving besides more reliable data. Similar studies had been carried out on Ligula intestinalis (JUHÁSZ, 1979b), on Taenia pisiformis (NÉMETH et al., 1979) and on Nippostrongylus brasiljensis (JUHÁSZ and KASSAI, 1981), when protease inhibitors, similar to the inhibitor of P. daubneyi had been described. (Recently, GOODMANN and PEANASKY, 1982, studied in a similar way, using affinity chromatography, the trypsin inhibitors of Ascaris described earlier. ) On the base of our experiments, the presence of trypsin chymotrypsin inhibitors is general among nematodes (N. brasiliensis

)

, cestodes (L. intestinalis, T

. pisiformis) as well as according to the hereby presented data among trematodes (P. daubneyi)

. These inhibitors are capable of inhibiting both trypsin and chymotrypsin, but not other well known proteases. The molecular weights of these inhibitors are low (5 000-10 000). The inhibitors resits pH and heat changes, their reaction with enzymes are timedependent, the resulting enzyme-inhibitor complexes are stable. Comparing the inhibitors studied by us and the inhibitors of Ascaris suum (KASSEL, 1970) and of Ascaridia galli (ANSARI et al., 1976), some differences can be established. Though the molecular weights of the latter inhibitors are low as well (4 650-22 000) and some other properties, such as stability, are similar to the properties of the inhibitors studied by us, there is an essential difference: the inhibitors of both A

. suum and A. galli are specific ones: they can inhibit only trypsin or only chymotrypsin. Present studies can not give any data on the biological function of the inhibitor of P. daubneyi. In the rumen of cattle the worm is not exposed to a serious effect of trypsin and chymotrypsin, so the protective function of the inhibitor is less probable than in the case of the other abovementioned worms. JUHÁSZ, S.: A Paramphistomum daubneyi bendőmétely faj proteáz-inhibitorának vizsgálata A szarvasmarha bendőmétely élősködőjének (

Paramphistomum daubneyi

) szomatikus kivonatából affinitáskromatográfiásan kinyertük részlegesen tisztított formában a tripszin- és kimotripszin-gátló anyagot. Enzimes előkezeléssel igazoltuk, hogy a két enzim gátlását az inhibitor ugyanazon (vagy két, egymással közeli szomszédos) aktív centruma végzi, tehát a P. daubneyi tripszin-kimotripszin inhibitorral rendelkezik. Az inhibitor gélkromatográfiásan mért molekulatömege 6 000. Az inhibitor hőstabil, pHváltozásnak, karbamid-kezelésnek ellenáll, de érzékeny 2-merkapto-etanolra. Az enzim-inhibitor komplex képződése időreakció. REFERENCES ANSARI, A.A. - KHAN, M.A. - GHATAK, S. (1976): Ascaridia galli: Trypsin and chymotrypsin inhibitors. - Expl. Parasit., 39: 74-83. BRAND, T. von (1979): Biochemistry and Physiology of Endoparasites

. - Elsevier/North-Holland Biomedical Press, Amsterdam. FEINSTEIN, G. (1971): Isolation of chicken ovoinhibitor by affinity chromatography on chymotrypsinSepharose. - Biochim. Biophys. Acta, 236: 73-77. GOODMAN, R.B. - PEANASKY, R.J. (1982): Isolation of the trypsin inhibitors in Ascaris lumbricoides var. suum using affinity chromatography. - Anal. Biochem.

, 120

: 387-393. HAJDÚ, É. - MATSKÁSI, I. - JUHÁSZ, S. (1979): Fasciola hepatica: Studies on protease and protease inhibitor activity. - Parasit, hung. , _12: 21-30. HALTON, D.W. - DERMOTT, E. (196-7): Electron microscopy of certain gland cells in two digenetic Trematodes. - J. Parasit., 53: 1186-1191.