1. Proteins Pgs. 101-103 Pgs. 71-80

2. Allosteric Enzymes  Allosteric enzymes have 2 sites. Active site of the enzyme Additional site where another substance can lock in When the other substance is locked in, the active site is non-functional

3. End Product Inhibition—a specific type of Allosteric Inhibition  As the end product accumulate, the steps in the product are stopped

4. Proteins: We Know That …  Proteins are built by condensation reactions between amino acids  Proteins have: Amino group, carboxyl group, H, all attached to a central carbon These are the functional groups that participate in condensation reactions Form peptide bonds

5. We know that …  20 amino acids What makes them different is their R group  Amino acids can be: acidic, basic, hydrophobic, hydrophilic  The 20 amino acids can be combined in any sequence, so there is a huge diversity of proteins

6. The structure of proteins  4 levels of structure: Primary Secondary Tertiary Quaternary  Remember, any change to a protein’s shape (at any level) can change its function

7. Primary  Sequence of amino acids  Attached by peptide bonds  Figure 5.18 (pg. 75)

8. Secondary  Parts of the polypeptide chain take up a particular shape  Folded and/or twisted α(alpha) helix β (beta) sheets These shapes are permanent, held by hydrogen bonds Between amino group and carboxyl group  Figure 5.20 (pg. 76)

9. Tertiary  Overall 3-D shape Precise, compact, unique to the protein  Due to interactions between the R groups of each amino acid  Bonding holds the structure: Hydrogen bonding Ionic bonding van der Waals interactions Disulfide bond – strongest

10. Quaternary  Some proteins consist of 2 or more polypeptide chains  Overall protein structure that results from the aggregation of polypeptide subunits  Complex, biologically active  Examples: Hemoglobin (4 polypeptide chains)

11. Denaturation  So, how does denaturation fit into all of this?

12. Functions of proteins  What are some functions of proteins?

13. Exit slip  List the 4 levels of protein structure.  Briefly outline the characteristics of each level.