Enzymes Helper Protein molecules Biology I Flow of

Enzymes: “Helper” Protein molecules Biology I

Flow of energy through life § Life is built on chemical reactions Biology I

Chemical reactions of life § Processes of life u building molecules § synthesis u breaking down molecules § digestion Biology I + +

Nothing works without enzymes! § How important are enzymes? u all chemical reactions in living organisms require enzymes to work § building molecules w synthesis enzyme + § breaking down molecules w digestive enzymes We can’t live without enzymes! u enzymes speed up reactions § “catalysts” Biology I enzyme +

Examples § synthesis + enzyme § digestion enzyme Biology I +

Enzymes are proteins § Each enzyme is the specific helper to a specific reaction each enzyme needs to be the right shape for the job u enzymes are named for the reaction they help u Oh, I get it! They end in -ase Biology I § § sucrase breaks down sucrose proteases breakdown proteins lipases breakdown lipids DNA polymerase builds DNA

Enzymes aren’t used up § Enzymes are not changed by the reaction used only temporarily u re-used again for the same reaction with other molecules u very little enzyme needed to help in many reactions u substrate active site Biology I product enzyme

It’s shape that matters! § “Lock & Key” model u u Biology I shape of protein allows enzyme & substrate to fit specific enzyme for each specific reaction

2 1 3 Biology I

Enzyme vocabulary § Enzyme u helper protein molecule § Substrate u molecule that enzymes work on § Products u what the enzyme helps produce from the reaction § Active site u Biology I part of enzyme that substrate molecule fits into

What affects enzyme action § Correct protein structure correct order of amino acids u why? enzyme has to be right shape u § Temperature u why? enzyme has to be right shape § p. H (acids & bases) u Biology I why? enzyme has to be right shape

Order of amino acids § Wrong order = wrong shape = can’t do its job! chain of amino acids DNA folded protein right shape! folded protein chain of amino acids DNA Biology I wrong shape!

Temperature § Effect on rates of enzyme activity Optimum temperature § greatest number of collisions between enzyme & substrate § human enzymes w 35°- 40°C (body temp = 37°C) u Raise temperature (boiling) § denature protein = unfold = lose shape u Lower temperature T° § molecules move slower § fewer collisions between enzyme & substrate u Biology I

Temperature reaction rate human enzymes 37° temperature Biology I What’s happening here? !

How do cold-blooded creatures do it? Biology I

p. H § Effect on rates of enzyme activity u changes in p. H changes protein shape u most human enzymes = p. H 6 -8 § depends on where in body § pepsin (stomach) = p. H 3 § trypsin (small intestines) = p. H 8 Biology I

p. H intestines trypsin What’s happening here? ! reaction rate stomach pepsin 0 Biology I 1 2 3 4 5 6 p. H 7 8 9 10 11 12 13 14

For enzymes… What matters? SHAPE! Biology I

Let’s build some Enzyme Models! Biology I