Properties of trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase in third-stage larvae of the nematode Anisakis simplex - preliminary studies

The activities of trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) were determined in third-stage larvae (L3) of Anisakis simplex. The optimum pH of TPS and TPP was 7.0 and optimum temperatures were 55 and 40 degrees C, respectively. The thermostability of TPP was found to be higher than that of TPS. The activity of TPS at 20-50 degrees C was approximately 20% of the maximum activity; at 65 degrees C the enzyme was inactivated. The activity of TPP at 25-30 degrees C was approximately 40% of the maxithum activity; at 60 degrees C the enzyme was inactivated. Effects of chemical compounds on the enzymes were determined. Supernatants used for enzyme preparations were obtained from homogenised worms spun for 15 min at 4 degrees C and 1500 g. TPS activity increased up to 25-fold under the influence of trehalose. In the case of fructose and sorbitol an inverse relationship was shown between concentration and enzyme activity. Proline was demonstrated to be another TPS inhibitor. TPS was activated by 20 mM MgCl2, NaCl and KCl. On the other hand, it was inhibited by CuCl2, CaCl2 and CoCl2. TPP was activated by 10 mM MgCl2, CaCl2, CoCl2, ZnCl2 and NaCl and 20 mM FeCl3, ZnCl, KCl and ethylenediaminetetra-acetic acid.