General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc Protein Hydrolysis and Denaturation Chapter 19 Amino Acids and Proteins

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.2 Protein hydrolysis  splits the peptide bonds to give smaller peptides and amino acids  occurs in the digestion of proteins  occurs in cells when amino acids are needed to synthesize new proteins and repair tissues Protein Hydrolysis

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.3 Hydrolysis of a Dipeptide  In the lab, the hydrolysis of a peptide requires acid or base, water, and heat.  In the body, enzymes catalyze the hydrolysis of proteins.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.4 Denaturation involves  the disruption of bonds in the secondary, tertiary, and quaternary protein structures  heat and organic compounds that break apart H bonds and disrupt hydrophobic interactions  acids and bases that break H bonds between polar R groups and disrupt ionic bonds  heavy metal ions that react with S—S bonds to form solids  agitation, such as whipping, that stretches peptide chains until bonds break Denaturation

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.5 Denaturation of protein occurs when  an egg is cooked  the skin is wiped with alcohol  heat is used to cauterize blood vessels  instruments are sterilized in an autoclave Applications of Denaturation

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.6 What are the products of the complete hydrolysis of the tripeptide Ala-Ser-Val? Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.7 What are the products of the complete hydrolysis of the tripeptide Ala-Ser-Val? The products are the three amino acids: alanine, serine, and valine. Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.8 Tannic acid is used to form a scab on a burn. An egg is hard-boiled by placing it in boiling water. What is similar about these two events? Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc.9 Tannic acid is used to form a scab on a burn. An egg is hard-boiled by placing it in boiling water. What is similar about these two events? Acid and heat cause the denaturation of protein. They both break bonds in the secondary and tertiary structures of proteins. Solution