3.1.4.2 Many proteins are enzymes Flashcards
Why are enzymes specific?
Each has a specific primary structure which consists of the sequence of amino acids. If order is changed, the tertiary structure which gives enzyme the 3D structure and active site will also change. Each active site is complementary to only one substrate
What is the induced fit model?
When enzyme and substrate collides, shape of active site changes so it’s complementary to the substrate - functional active site
How does the shape of an enzyme molecule relate to its function
It has a specific 3D tertiary structure which is complementary to the substrate, allowing it to fit into its active site.
How does pH effect enzyme’s activity?
Too acidic - contains H+ ions, makes amino acid positively charged
Too alkali - contains OH- ions, makes amino acid negatively charged
Charge of amino acids effect bonds formed due to electro negativity
Tertiary structure changes - different active site is formed - no longer complementary to substrate - less enzyme-substrate complex formed
How does temperature effect enzyme’s activity?
Too high - breaks bonds of structure, changes shape of active site - no longer complementary with substrate - less enzyme-substrate complex formed
Too low - enzymes doesn’t move fast enough for successful collision
What are the factors that affects enzyme’s activity?
Temperature, pH, enzyme + substrate concentration, inhibitors (competitive and non-competitive)
How do competitive and non-competitive inhibitors differ in terms of binding with enzyme?
Competitive inhibitors binds to the active site as it has a similar shape to the substrate - complementary
Non-competitive inhibitors binds to site, bonds will form between inhibitor and enzymes, other bonds will break and this changes the tertiary structure. Shape of active site changes
How do substrate’s concentration affect competitive and non-competitive inhibitors differently?
Competitive inhibitors can be overcome by increasing substrate concentration
Non-competitive inhibitors cannot - shape of enzyme is changed permanently - no more enzyme-substrate complex
What is the induced fit model of enzyme?
Before interaction of enzyme and substrate, enzyme’s active site is not complementary to substrate. When they interact, enzyme changes the shape of its active site (becomes functional) and this puts strain onto the substrate. This makes certain bonds easier to break which lowers the activation energy
