Enzymes - Biology?

Question

What would happen to an enzyme-facilitated reaction if temperature were increased. What would be the effect if temperature were increased to 100 degrees Celsius?

What is the optimal temperature (degrees C) for enzymes functioning in the human body?

How does a competitive inhibitor affect the rate of an enzyme-mediated chemical reaction?


Really stuck on these questions. :/ Any help is appreciated.

Answer 1

The above answers plus:

there are enzymes that can withstand very high temperatures without being denatured for instance Thermus aquaticus DNA polymerase or short taq Polymerase. This enzyme is used for PCR, a technique to multiply DNA in vitro which uses repeated steps of 93-95C to denature DNA.

There are actually also bacteria that live optimally near the boiling point. So their enzymes have to be also very heat resistant.

Answer 2

1. Increasing temperature slightly may speed up the reaction because molecules would move around more quickly. But notice that word "slightly". Higher temperatures denature enzymes. If the temperature were increased to 100 C, the protein (enzyme) would have been denatured or destroyed long before it got that hot.

2. Optimal temperature for enzyme action in the human body should be normal body temperature - 37 C.

3. A competitive inhibitor binds to the active site of the enzyme, so the enzyme is already "busy" and doesn't have an active site free for its usual substrate. That's the competition. Which one gets the active site - the inhibitor instead of the substrate.

Answer 3

Enzymes act as catalysts. At catalyst does not alter a chemical reaction in anyway. If a chemical reaction is going to take place it is going to go from a higher energy state to a lower energy state, however, the chemicals involved have to pass through what is called a transition state which is often higher energy than both the reactants and the products. See the link for a diagram of energy states and the role of catalysts. In order for the reaction to proceed it has to get over this "energy hump." One way for this to occur is simply to supply more energy (the laboratory reactions in your example). Another way is to use a catalyst (in this case, the enzyme). The enzyme stabilizes the transition state and lowers the "energy hump." So that the reaction can run to completion at a lower temperature.

Answer 4

enzymes usually function best at body temperature (thats what they're designed for) or 37degrees C. The work faster at higher temperatures, but if they are heated up to much, the proteins within the enzymes will denature, causing them to be biologically inactive and useless.