3.6.3 - Explain the effects of temperature, pH and substrate concentration on enzyme activity Temperature -Each enzyme has an optimal temperature for function. When at this temperature, the enzyme will work at its peak, speeding up the reaction. After the temperature reaches its optimum level, the reaction rate abruptly declines. Many enzymes are adversely affected by high temperatures, at which point denaturation occurs. Many enzymes only have a narrow range of conditions under which they operate properly. This is usually at low temperatures for plant and animal enzymes.
pH -Enzymes also have an optimal pH. At this point, it works best and the reaction will happen the fastest, as the enzyme is the most active. Extremes in pH will usually result in a complete loss of activity for most enzymes. Theoptimum pH for each enzyme varies greatly. For example, pepsin has an optimum pH of 1.5, but lipase has an optimum pH of 8.0.
Substrate Concentration - If the amount of the enzyme is kept constant and the substrate concentration is increased, the reaction velocity will increase until it hits its maximum. After that, the velocity plateaus. At this point, all of the enzymes have formed complexes with the substrates.
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