Enzymes Organic molecules part 2 What are we

Enzymes Organic molecules part 2

What are we learning today? SB 1. b Explain how enzymes function as catalysts.

Enzymes? • Enzymes are special proteins. • They are catalytic molecules. That is, they speed up specific reactions without being used up in the reaction.

Common features • They don't make it happen. . they just speed it up! • They are not permanently altered or used up in the reactions. • The same enzyme works for the forward and reverse directions of a reaction. • Each enzyme is highly selective about its substrate.

So, how does it work? • The enzyme holds • The lock and key the substrate in mechanism – the right position, lock is the enzyme and once the itself and the key reaction is is the substrate. completed, the • When the enzyme unlocks substrate fits into the product. the active site on the enzyme, it is called an enzymesubstrate complex.

Speed limits. . . how many are there?

Speed limits. . . too hot? cold? • Temperature can also affect the speed. Typically they speed up the higher the temperature (unless too hot), and slows down the cooler the temperature.

How much power? • Activation energy is the minimum amount of energy that molecules must collide with so they can reach the transition state. • Then they can react spontaneously.

Going for a drive. . . • The higher the energy hill (the more activation energy required) the slower the reaction time. Conversely, the lower the energy hill, the faster the reaction time.

Meet some enzymes. . . • Lipase, which is made in the pancreas, function is to digest lipids in the small intestines.

Meet some enzymes. . . • RNA polymerase facilitates the process of RNA transcription (the making of new RNA).

Missing them. . . • Some disease are caused by the inability to create an enzyme, or a faulty enzyme. • Tay-Sachs is a disease that is caused by the lack of Hexosaminidase A, which breaks down lipids in the brain and other nerve cells.

Missing them. . . • Lactose intolerance (AKA Lactase Deficiency) is a disease caused by the lack of the enzyme lactase which breaks down the milk sugar called lactose.

• To see how they work in motion Enzyme activity 01/27/07