Enzymes are specialized proteins. Instructions for making proteins are encoded in DNA.

Catalysts Enzymes are catalysts made by living things. Catalysts lower the activation energy of reactions. Catalysts speed up the rates of chemical reactions in cells.

Enzymes lower the activation energy needed for chemical reactions!!!

The special molecule with which an enzyme reacts is called the substrate. Enzymes remain unchanged in chemical reactions and can be used over and over again on many substrate molecules.

 are usually named by adding -ase to the name of their substrate (ex. amylose is the substrate for amylase)

 are specific--most enzymes interact with only one substrate  shape is critical to function--each enzyme has a specific “active site” to which the substrate binds

 tend to function in a narrow range of temperature and pH. At extremes of pH or temperature, enzymes are denatured and no longer function properly as the active site is so altered it can not bind to the substrate.

Where in the digestive tract do you think chymotrypsin is located? Where do you think you find pepsin in the human body? Yes--in the small intestine! In the stomach--you’re right!

 induced fit model suggests that the enzyme changes its shape slightly to accommodate the substrate (replacing the “lock and key” model)

 Note the enzyme is not used up in the reaction. The enzyme is unchanged.

 are coded for by genes; thus, many genetic disorders are the result of faulty or missing enzymes (ex. PKU) Buildup of phenylalanine is toxic to the central nervous system. Untreated, PKU leads to severe brain damage. Victims often have IQs below 60.

Now, infants are tested, and are put on a strict diet that limits phenylalanine.

Albinism results from a missing enzyme needed to produce melanin.

What group of substrates are catalyzed by the group of enzymes known as proteases? PROTEINS What enzyme catalyzes the substrate glucose? GLUCASE