Themes: Structure meets Function Enzymes Themes: Structure meets Function
Objectives How does the structure of an enzyme affect its function?
Chemical reactions in living things Many important biological reactions (such as dehydration synthesis) happen very slowly. The substrates (ingredients) have to be in the right position
Enzymes Catalysts: Speed up reactions They align substrates correctly Shape is important!
How do enzymes work?
On the previous slide, be able to label: Enzyme (catalyst): Speeds up reaction Substrate: Material the enzyme is changing. (what you start with) Products: what you end with Active site: Portion of the enzyme that is interacting with the substrate.
Structure Meets Function Enzymes have a very specific shape. An enzyme cannot act on a substrate unless it fits like a “lock and key”
4 levels of structure Primary: sequence of amino acids Secondary: folding caused by H-bonding Tertiary: folding caused by ionic, hydrophobic, or disulfide bonds Quaternary: multiple subunits
4 levels of structure
Homeostasis of Enzymes What four factors affect enzyme activity: pH Temperature Enzyme Concentration Substrate Concentration
Denatured Protein Denaturation: When environmental conditions change the structure of the enzyme so that it can NO longer function (ever again!!!)
What affects how enzymes work?
Enzyme inhibitors Competitive inhibition: another molecule competes for the active site. Allosteric inhibition: something binds to the enzyme and changes the shape of the active site.