Dr. Murai Éva szerk.: Parasitologia Hungarica 12. (Budapest, 1979)

Group 3 Bovine trypsin (BDH) or bovine chymotrypsin (REANAL) of known activity was added to flukes incubated in TC 135 medium. Medium samples similarly incubated, and containing the same level of enzyme, but no fluke, were used as control. All media were assayed for protease activity after 24 hours incubation. Table 3 BTEE-splitting activity in 0.2M Na-phosphate and Na-phosphate-HCl buffer pH 3. 5 4 5 6 7 8 9 BTEE-splitting activity U/g 13 25 2. 4 0. 5 0. 8 1. 0 0. 6 Group 4 Flukes were incubated in Tyrode medium, containing 0. 3 M TRIS-HC1 buffer and bovine proteases of known activity, on the following schedules: a. 1 ml Tyrode + 0.1 ml, 0. 1% trypsin + fluke b. same as in "a", with oral sucker of fluke closed c. 1 ml Tyrode + 0.1 ml, 0. 1% chymotrypsin + fluke d. 1 ml Tyrode +0.1 ml, 0. 1% chymotrypsin (control) e. same as in "d", with oral sucker of fluke closed f. 1 ml Tyrode +0.1 ml, 0. 1% chymotrypsin (control). Table 4 Haemoglobin degrading activity of the liver fluke somatic extract (Pepsin and cathepsin-like enzyme determination) Buffer 0.3N HCl (pH 1.5) 0.04M Náci träte (pH 2. 8) § 1.35M CH

3 COOH0.02M (NH

4

)

2

S0

4 (pH 3. 5) § 0.4M citric acid-0.8M NaOH (pH 5.0) § A

E

280 0. 28 0. 52 0. 42 0. 50 + 0. 07M cystein-HCl A

E

280 0.94 0. 96 0.97 + MYCEK (1970). § RYLE (1970). Incubation lasted 4 hours at 37°C in all experimental and control series. Protease activity was determined on BAEE (N- ot- benzoyl-L-arginine-ethylester) (SCHWERT and TAKENAKA, 1955) or BTEE (N-benzoyl-L- tyrosine-ethylester) substrate (HUMMEL, 1959), using a Unicam SP 1800 Ultraviolet spectrophotometer, with thermostated cuvettes and an AR25 Linear Recorder. All assays were carried out at 30°C, after 5-min