Factors Effecting Rate of Enzyme Action: Study Notes

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Factors Affecting the Rate of Enzyme Reactions

• Enzyme concentration: The rate of the reaction is directly proportional to the concentration of the enzyme, provided that the substrate concentration is high and other factors like pH and temperature remain constant. As the concentration of enzymes increases, the rate of the enzyme reaction also increases.
• Substrate concentration: The rate of reaction increases with substrate concentration up to a point where the active sites of all enzyme molecules are fully occupied (saturation point). After this point, adding more substrate does not increase the reaction rate because the enzyme active sites are already saturated.
• Temperature: Enzymes have an optimum temperature at which they exhibit maximum activity. If the temperature exceeds this optimal point, the enzyme may become denatured, resulting in a decrease in reaction rate. Lower temperatures do not denature the enzyme, but they reduce its activity, and the enzyme can regain activity once the temperature is restored.
• pH: The rate of the enzyme reaction is highest at a specific optimum pH. Changes in pH can alter the ionic charges of the amino acid residues in the enzyme, leading to changes in its shape, including that of the active site, which may reduce or stop the enzyme's activity.
• Water: Water is essential for enzyme function. In certain processes, such as germination, increasing water levels activates enzymes, facilitating the breakdown of stored nutrients and promoting growth.
• Radiation: Ultraviolet light, as well as beta (β) rays, gamma (ɣ) rays, and x-rays, can rapidly inactivate enzymes by disrupting their structure, leading to a loss of enzymatic activity.

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