Всероссийский научно-исследовательский институт физиологии, биохимии и питания животных – филиал Федерального государственного бюджетного научного учреждения «Федеральный научный центр животноводства – ВИЖ имени академика Л.К. Эрнста»
ABSTRACT. It is known that the effect of enzymes of food objects on the digestive processes in fish largely depends on the type of consumer and prey, temperature and pH of the gastric and enteral media. In recent decades, various anthropogenic factors, including phenol derivatives, have a significant effect on the activity of digestive hydrolases. The aim of this work was to study the effect of phenol on the temperature characteristics of casein-lytic and hemoglobin-lytic peptidases that function in the body of chironomid larvae. Effects of phenol studied in the homogenate of larvae of chironomids Chironomus sp. in the temperature range 0-70 ° C, pH 7.4. The ratio of volumes of homogenate and phenol with an initial concentration of 0.1 mM (9.41 mg/l) is 1: 1. The final concentration of phenol during preincubation and incubation is 0.025 mM (2.35 mg/l). One hour after the start of the pre-incubation, a substrate (casein or hemoglobin, pH 7.4) was added and the mixture was incubated for 30 minutes in thermostatically controlled chambers. The activity of peptidases was assessed by the increase in the concentration of tyrosine. In the temperature range 0-30°C, the temperature coefficients (Q10) were determined and the values of the activation energy were determined graphically (according to temperature dependence). Under the influence of phenol, the activity of casein and hemoglobin-lytic peptidases at 20°C increases by 1.2 and 1.9 times, respectively. Phenol did not affect the value of the temperature optimum for the activity of casein- and hemoglobinlytic peptidases of chironomid larvae in the range 0-30 ° C, but changed the shape of the temperature dependence curves due to a sharp increase in enzymatic activity at 40°C (P<0.05). Changes in Q10 and the energy of activation (Eact) under the influence of phenol are noted. In the presence of phenol, the values Eact of hydrolysis of hemoglobin in the 0-20°C zone vary at a higher temperature in different directions: at low temperatures they increase by 1.2 times, in the zone of higher temperatures they decrease by 1.3 times. The data obtained indicate a significant effect of phenol on the activity and temperature characteristics of peptidases of chironomid larvae, which can affect the digestive processes of benthophagous fish actively consuming chironomid larvae.
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