Enzymes Helper Protein molecules Flow of energy through

Enzymes: “Helper” Protein molecules

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

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 § Biological catalysts enzyme +

Enzymes are proteins § Each enzyme is the specific helper to a specific reaction Must 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 § § 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 – like a taxi u re-used again for the same reaction with other molecules u very little enzyme needed to help in many reactions u substrate product active site enzyme

It’s shape that matters! § Lock & Key model § Induced Fit Model u shape of protein allows enzyme & substrate to fit

Enzyme vocabulary § Enzyme u Biological catalyst: helper protein molecule § Substrate u molecule that enzymes work on § Products u what is produced in reaction. § Active site u part of enzyme that substrate molecule fits into

What affects enzyme action § Correct protein structure § Temperature § p. H (acids & bases)

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 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 temperatures § molecules move slower § fewer collisions between enzyme & substrate u

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

p. H (Acids and Bases) § 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

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

For enzymes… What matters? SHAPE!