Question

Почему при высоких температурах ферментативные реакции останавливаются?​

Answer 1

При увеличении температуры выше 50° С, причем скорость денатурации при нагревании увеличивается во много раз быстрее, чем скорость любого химического превращения. Поэтому процесс инактивации, связанный с уменьшением концентрации фермента в системе, обусловливает при дальнейшем повышении температуры замедление реакции.

Answer 2

Why do enzymatic reactions stop at high temperatures?

Enzymatic reactions are biochemical reactions that are catalyzed by enzymes. Enzymes are proteins that act as catalysts, speeding up the rate of chemical reactions in living organisms. However, at high temperatures, enzymatic reactions can be affected and may even stop. This is primarily due to the denaturation of enzymes.

Denaturation is the process by which the three-dimensional structure of a protein, including enzymes, is disrupted or altered. Enzymes have a specific three-dimensional structure that is crucial for their function. This structure is maintained by weak interactions, such as hydrogen bonds, hydrophobic interactions, and disulfide bonds.

When the temperature increases, the kinetic energy of the molecules also increases. This increased kinetic energy can disrupt the weak interactions that maintain the enzyme's structure. As a result, the enzyme loses its shape and becomes denatured. Denatured enzymes are unable to bind to their substrates and catalyze the reaction effectively, leading to a decrease or complete halt in enzymatic activity.

Additionally, high temperatures can also cause the breaking of covalent bonds within the enzyme molecule, further contributing to its denaturation. The disruption of the enzyme's structure and the breaking of covalent bonds can irreversibly damage the enzyme, rendering it non-functional.

It is important to note that different enzymes have different temperature optima, which is the temperature at which they exhibit maximum activity. Enzymes from thermophilic organisms, such as those found in hot springs, have evolved to function optimally at high temperatures. However, most enzymes in organisms that live in moderate temperatures, including humans, have temperature optima around 37°C (98.6°F).

In summary, enzymatic reactions stop at high temperatures primarily due to the denaturation of enzymes, which disrupts their three-dimensional structure and renders them non-functional.