The Effect of Phenol on the Activity and Temperature Characteristicsof Peptidases in Chironomid Larvae at Different рН Values
The effect of phenol (Ph, 0.25 mmol/L) on the activity and temperature dependence of casein- and hemoglobinlytic peptidases functioning in the whole organism of chironomid larvae Chironomus sp. within the temperature range of 0−70ºС at different рН values (3.0, 5.0 and 7.4) was investigated. The temperature optimum of the studied peptidases of chironomid larvae corresponds to 40°С. Under the influence of phenol, the activity of caseinlytic peptidases increases, more significantly at 20°С and рН 5.0 (3.3 times), that of hemoglobinlytic peptidases – at рН 3.0 (3.5 times). The effect successively decreases from рН 3.0 up to рН 7.4. under both temperatures. In the presence of phenol, the shape of the curves of the temperature dependence and the Q10 values transform most significantly in the zone of high temperatures. The values of activation energy (Eact) of the process of hydrolysis of casein and hemoglobinlytic peptidases in the zone of low and high temperatures are different. In the presence of phenol, Eact values of the process of hydrolysis of casein caseinlytic peptidases at рН 7.4 are increased, at рН 5.0 they decreased in the zone of high temperatures. Eact values of the process of hydrolysis of hemoglobinlytic peptidases are decreased in most cases. The mechanisms of the influence of phenol on peptidase activity and digestive processes in fish-benthophagous eating of chironomid larvae are discussed.