Denaturation in enzymes Flashcards
What are the two factors that can cause denaturation?
- pH
- Temperature
Is an enzyme a protein, carbohydrate or fat?
An enzyme is a protein
If a protein is denatured, what levels structure are effected?
Secondary, tertiary, and quaternary structure
Why is primary structure not effected when an enzyme is denatured?
The primary structure of an enzyme consists of covalent bonds which are less likely to be broken compared to that of the secondary, tertiary and quaternary structure
What is the term to describe an enzyme being denatured and turning from a liquid to a solid?
Coagulation. (An example would be egg whites being whipped - going from a liquid to a solid)
What is an enantiomer/optical isomer?
An enantiomer is two different structures (a carbon bonded to 4 different molecules) that are mirror images of each other and are not super imposable
In an enantiomer/ optical isomer what are the carbon atoms described as?
They are described as being chiral centres
Does a decrease in temperature lead to the denaturation of enzymes?
No it doesn’t. Decreasing the temperature will slow the activity of the enzymes down, so it takes longer for a reaction to occur. It does not denature them, but rather freezes them, and when the temperature rises again they will resume function.
When there is an increase in temperature, what happens to enzymes?
When there is an increase in temperature the enzymes are denatured. This is where the structure of the enzyme is altered, which effects the shape of the active site. With a change in the active site it means the substrate can’t bind to the enzyme, so a reaction cannot occur (Lock and key becomes redundant). Therefore high temperatures cause enzymes to denature, which slows and or ceases the activity of catalysing substances.
What effect does pH have on enzymes?
pH can cause enzymes to denature. This is where the structure of the enzyme is altered, which effects the shape of the active site. With a change in the active site it means the substrate can’t bind to the enzyme, so a reaction cannot occur (Lock and key becomes redundant). Therefore changes in or high pH, causes the enzymes to denature which slows and or ceases the activity of catalysing substances.
Are all amino acids in the body Chiral?
Yes, except for glycine (l or d form). This also means that all enzymes in the body are chiral
Can enzymes distinguish between enantiomers of a chiral substance?
Yes they can, as enantiomers have different 3D shapes, that may interact with the active site of an enzyme differently. Only one of the enantiomers may fit the active site and be able to participate in the reaction, therefore that is the only enantiomer that is biologically active
When an enzyme is denatured what happens to the alpha helix and beta sheets?
The alpha helix and beta sheets uncoil when an enzyme is denatured. This results in a change in shape and ultimately means there are weaker Hydrogen-bonds
Does optical isomers effect the ability to bind to the active site of an enzyme? (lock and key)
Yes it does. Regardless of wether it is the same substrate used, if the shape is not correct, it will not fit into the active site and a reaction cannot occur. This links to the lock and key model. A substrate will only fit in the active site of an enzyme if the shape is correct. otherwise a reaction will not occur
How can we determine the best conditions for enzymes to catalyse substances in?
We measure the reaction rates of enzymes under different conditions, the highest/quickest reaction rate is the best conditions for the enzyme to function in. Whereas a lower/slower reaction rate suggests the enzyme can’t function as efficiently under those conditions.
