1. 1.What makes an enzyme specific to one type of reaction (in other words, what determines the function of a protein)? –SHAPE determines the function of a protein and makes enzymes specific to one reaction 2.How does heating (boiling) affect the ability of an enzyme to perform its function? –Heating/boiling denatures enzymes (unfolds them) and makes them lose their function

2. What will we learn today? HOW is the shape of a protein determined? WHY does heating/boiling denature enzymes and make them lose their function? Also : What makes hair straight or curly and how do perms work? Why is it important to eat different types of food to supply our protein needs?

3. Proteins are made of chains of amino acids What are amino acids? Link to amino acid 3-D models

4. H2NH2N Amino group C Side chain R H C O OH Carboxyl group Non-ionized form There are 20 different amino acids. All have the same general form.

5. CC O O–O– H H3N+H3N+ H Glycine (G) Gly CC O O–O– H H3N+H3N+ CH 3 Alanine (A) Ala CC O O–O– H H3N+H3N+ CH H3CH3C CH 3 Valine (V) Val CC O O–O– H H3N+H3N+ CH 2 H3CH3C CH 3 Leucine (L) Leu CH CC O O–O– H H3N+H3N+ Isoleucine (I) Ile CH 3 CH 2 H3CH3C These side chains contain only carbon and/or hydrogen C O O–O– C CH 2 H2CH2C H2N+H2N+ H Proline (P) Pro Each amino acid has a different side chain.

6. C H3N+H3N+ CH 2 H C O O–O– Phenylalanine (F) Phe C H3N+H3N+ CH 2 H C O O–O– Tyrosine (Y) Tyr OH C H3N+H3N+ CH 2 H C O O–O– NH Tryptophan (W) Trp Side chains contain ring structures Each amino acid has a different side chain.

7. CH 3 CH 2 S CC H3N+H3N+ H O O–O– Methionine (M) Met SH CH 2 CC H3N+H3N+ H O O–O– Cysteine (C) Cys Side chains contain sulfur Each amino acid has a different side chain.

8. OH CH 2 CC H3N+H3N+ H O O–O– Serine (S) Ser Threonine (T) Thr CH CC H3N+H3N+ H O O–O– CH 3 HO Side chains contain hydroxyl [OH] functional groups Each amino acid has a different side chain.

9. C CH 2 CC H3N+H3N+ H O O–O– H2NH2N O Asparagine (N) Asn CH 2 CC H3N+H3N+ H O O–O– C O H2NH2N Glutamine (Q) Gln Side chains contain amino [NH2] functional groups Each amino acid has a different side chain.

10. CH 2 C C H3N+H3N+ H O O–O– NH + NH Histidine (H) His CH 2 CC H3N+H3N+ H O O–O– + NH 3 CH 2 Lysine (K) Lys Basic side chains CH 2 C C H3N+H3N+ H O O–O– NH C + NH 2 NH 2 Arginine (R) Arg Each amino acid has a different side chain.

11. CH 2 CC H3N+H3N+ H O O–O– C O–O– O Aspartate (D) Asp Acidic side chains CH 2 CC H3N+H3N+ H O O–O– C O–O– O Glutamate (E) Glu Each amino acid has a different side chain.

12. H HHHHHHOOOHHOHHO NCCNNCCCC H CH 3 CH 2 OH N-terminus NCC CH 2 C O OH CH 2 NCC CH CH 3 H3CH3C CH 2 OH HHO NCC HHO NCC H HO NC C CH 2 SH OH C-terminus H2NH2N H H C C O OH Carboxyl group H2NH2N H CH 3 CC O OH Amino group H2NH2N H H C O C NC C H H CH 3 OH O Peptide bond +H2OH2O H2NH2N GlyAlaSer Asp N-terminus 21354678 PheValTyrCys C-terminus COOH + Proteins are chains of amino acids

13. Amino Acid sequence determines the 3-D protein shape Interactions between amino acids cause folding and bending of the chain Examples: –positive (+) and negative (-) parts of amino acids are attracted to each other. –hydrophobic regions are attracted to each other Folding http://www.stolaf.edu/people/giannini/flashanimat/proteins/hydrophobic%20force.swf Structure levels http://www.stolaf.edu/people/giannini/flashanimat/proteins/protein structure.swf

14. CH 2 OH CH 2 C O N H H Hydrogen bond between two side chains CH 2 OH OC OC H N CH 2 CH CH 3 Hydrogen bond between side chain and peptide group Hydrogen bond between peptide groups H3CH3C H3CH3C CHCH 2 Hydrophobic interaction CH 2 SS Disulfide bond Ionic bond (CH 2 ) 4 NH 3 + –O–O O CCCH 2 Figure 3.11a Interactions that determine the structure of proteins

15. A tertiary structure composed mostly of  -helices A tertiary structure composed mostly of  - pleated sheets A tertiary structure rich in disulfide bonds Figure 3.11b Tertiary structures are diverse.

16. Paper polypeptides activity Peptides are chains of amino acids and sometimes used as another word for protein. Follow the instructions of your teacher to build peptides using the paper amino acid models.

17. Straight, curly, and “permed” hair

18. Explain the connection between the order of the amino acids and the shape of the protein. Why did the boiled lactase not work any more? (base your answer on the paper model)

19. ESSENTIAL AMINO ACIDS

20. Essential amino acids and nutrition Consider why protein is needed and what amino acids and proteins are used for in the body. Describe the symptoms you would expect a person with protein deficiency to have. Look at Table 1. Which amino acids does corn lack (not have)? Which amino acids do beans and legumes lack (not have)? Vegans are vegetarians that do not eat any food from animals, including milk and eggs. Why must vegans combine foods from a variety of plant sources to avoid protein deficiency (for example rice and beans instead of only beans)? A new protein supplement for athletes and weightlifters advertises that it is the best because it is made of “100% natural organic corn protein”. Why would this not be a good product for athletes and weightlifters?