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Factors that affect enzymatic rxns -pH -temperature -enzyme concentration substr

ID: 3505965 • Letter: F

Question

Factors that affect enzymatic rxns -pH -temperature -enzyme concentration substrate concentration -activators, inhibitors, cofactors, etc Effects of Temperature Optimal temp. All human enzymes optimal temp.- 37°C (98.6°F) .Cold slows activity Extreme heat 0 5 10 15 20 25 30 35 40 45 Temperature Understand the graph of reaction rate versus temperature (Slide 13). What is the relationship between reaction rate and temperature between 0 degree C and 35 degrees C? What happens to reaction rate above 37 degrees C, and what cause the abrupt change in function? What is the abrupt change called? Is it a reversible or an irreversible change?

Explanation / Answer

All enzymes have an optimal temperature for reaction i.e the temperature at which its reaction rate is maximum. This optimal temperature is around 37 degrees for most of the enzymes, but could vary a little. At low  temperatures the activity of the enzyme is low, as  temperature increases the kinetic energy of the enzyme molecule as well as the substrate increases and the chances that they will collide with each other, is quite high and so the reaction will occur. However, when all the molecules of the substrate have been occupied by enzyme molecules, the maximum reaction rate will be achieved and the graph will reach the plateau.

If the temperature increases far beyond this optimal  temperature (usually 37 degrees), the enzyme will be slowly denatured and the activity will be lost and the reaction will slower down and then stop. The temperature at which an enzyme denatures depends on the structure of the enzyme. This enzyme denaturation is considered an irreversible process i.e structure of the enzyme changes. However, there are evidences when the enzyme has denatured or unfolded a little, it can renature again.