Factors affecting the use effect of enzyme preparations

In the pursuit of green and low-carbon life, enzyme preparations have penetrated into all aspects of our lives with the characteristics of high efficiency, safety, no toxic side effects and little impact on the environment. For example, the bread and steamed bread we eat, the juice and beverage we drink, the seasoning for cooking, and the paper documents we use can all use enzymes. Therefore, understanding the chemical nature of enzyme preparations is of great significance for the correct use of enzyme preparations.

1. The influence of pH value

Each enzyme only exhibits high activity in a specific pH range, which is the optimum pH for enzyme action. Generally speaking, the enzyme is most stable at the optimum pH value, so the pH value of the enzyme action is also its stable pH value. If the pH value of the enzyme reaction is too high or too low, the enzyme will be irreversibly damaged, and its stability, activity will decrease, or even inactivation. The optimum pH range of different enzymes is different, and there are some acidic, neutral and alkaline. For example, according to the optimal pH value of protease, it is often divided into acidic protease, neutral protease and alkaline protease. The pH value of enzyme action is also a parameter measured under certain conditions. The optimum pH of the enzyme is different depending on the temperature or substrate. The higher the temperature, the narrower the stable pH range of the enzyme. Therefore, in the process of enzyme-catalyzed reaction, the pH value of the reaction must be strictly controlled.

2. The influence of temperature

Under certain conditions, each enzyme has an optimal temperature. At this temperature, the enzyme activity is the highest, the effect is the best, and the enzyme is relatively stable. The speed of the enzyme catalyzed reaction increases and the thermal denaturation loss of the enzyme activity reaches a balance. , which is the optimum temperature for enzyme action. Each enzyme has a temperature at which its activity is stable. At this temperature, under a certain time, pH and enzyme concentration, the enzyme is relatively stable, and no or very little activity decline occurs. This temperature is the stable temperature of the enzyme. Above the stable temperature, the enzyme will be rapidly inactivated. This thermal sensitivity of the enzyme can be expressed by the critical failure temperature Tc, which refers to the temperature at which the enzyme loses half of its activity in 1 hour. Therefore, generally only within the effective temperature range of the enzyme, can the effective catalysis be carried out. For every 10 °C increase in temperature, the enzyme reaction speed increases by 1 to 2 times. The effect of temperature on the action of the enzyme is also related to the time it is heated. The longer the reaction time is, the lower the optimum temperature of the enzyme. In addition, factors such as the substrate concentration, buffer type, activator and enzyme purity of the enzyme reaction will also change the optimal temperature and stable temperature of the enzyme.

3. The effect of enzyme concentration and substrate concentration

The substrate concentration is the main factor that determines the rate of enzyme-catalyzed reaction, under certain conditions of temperature, pH and enzyme concentration. When the substrate concentration is very low, the catalytic reaction rate of the enzyme increases rapidly with the increase of the substrate concentration, and the two are proportional. As the substrate concentration increased, the reaction rate slowed down and no longer increased proportionally. The relationship between substrate concentration and enzyme-catalyzed reaction rate can generally be expressed by the Mie equation. Sometimes the substrate concentration is very high, and the enzyme reaction speed is also reduced due to substrate inhibition. When the substrate concentration greatly exceeds the enzyme concentration, the enzyme-catalyzed reaction rate is generally proportional to the enzyme concentration. Also, if the enzyme concentration is too low, the enzyme sometimes fails, preventing the reaction from proceeding. For the enzyme-catalyzed reaction in food processing, the amount of enzyme is generally much less than that of the substrate, and the cost of the enzyme should also be considered.

4. The effect of inhibitors

Many substances can weaken, inhibit, or even destroy the action of enzymes. These substances are called enzyme inhibitors. Such as heavy metal ions (Fe3+, Cu2+, Hg+, Pb+, etc.), carbon monoxide, hydrogen sulfide, organic cations, ethylenediamine and tetraacetic acid, etc. In actual production, it is necessary to understand and avoid the influence of inhibitors on enzyme catalysis.

5. The effect of activators

Many substances have the effect of protecting and increasing the activity of enzymes, or promoting the conversion of inactive enzyme proteins into active enzymes. These substances are collectively referred to as enzyme activators. Activators can be divided into three categories: the first category is inorganic ions, such as Na+, K+, Ca2+, Mg2+, Cu2+, Co2+, Zn2+ and other cations, and Cl-, NO3-, PO43-, SO42- and other anions. The second category is organic matter with smaller molecules, mainly vitamin B group and its derivatives. The third category is macromolecular substances with protein properties. The effect of activator on the rate of enzyme-catalyzed reaction is similar to that of substrate concentration, but it is rarely used in practical production.

6. The impact of preservation of the environment

The enzyme preparation is in a dormant state under low temperature environment. To keep the enzyme for a long time without losing its activity, the enzyme activity is lost by 5-10%/6 months when stored at 10°C, and the enzyme activity is lost by 10-15%/6 months when stored at room temperature. So the key is the environment is dry and low temperature. Both heat and light can easily inactivate the enzyme, therefore, the enzyme preparation should be stored in a low temperature and dark place. In addition, the higher the moisture content of the enzyme preparation, the easier it is to inactivate, so the general powdered enzyme preparation is easy to store and transport. In addition, some metal ions can also cause the enzyme to lose activity or inhibit the activity of the enzyme, and the container of metal ions should be avoided to store the enzyme preparation.