Enzymes

Unit 5 1/2

A chemical reaction will occur spontaneously…

but the process may be too slow to be effective, in living cells…

A chemical reaction will occur spontaneously, but the process may be too slow to be effective, in living cells…

ex. hydrolysis of sucrose:

adding water~ they break apart

ex. hydrolysis of sucrose:

energy is required to break the bond between those two carbohydrate molecules,

ex. hydrolysis of sucrose:

+ adding water~ they break apart

Chemical reactions can’t “get started” w/o energy being added • In other words… ENERGY must be added in order for the reaction to start… • Kinda like you cannot put keys on a ring… without opening the ring first!

ex. hydrolysis of sucrose:

energy required to break bonds = Activation Energy it is EXTREMELY HIGH!

ex. hydrolysis of sucrose:

Activation energy!!

ex. hydrolysis of sucrose:

Activation Energy - -

the reaction can occur only when energy is

ACTIVATION ENERGY

can give off heat

hydrolysis of molecules in your body…

Energy of Activation EA barrier is EXTREMELY high - the reaction will occur only if reactantsed:

Energy of Activation EA barrier is EXTREMELY high - the reaction will occur only if reactants are heated:

Enzymes lower the temperature of the activation Energy energy - of

Activation EA barrier is EXTREMELY high - the reaction will occur only if reactants are heated:

Enzymes lower activation energy so rxn. can occur Too hot!!!

AHHHHH!!!

Enzymes lower activation energy this allows chemical reactions to happen in your body FASTER!!

Bromelai n Pineapple has been used as a medicinal plant in several native cultures and bromelain has been known chemically since 1876. Bromelain is a digestive enzyme found in the stem and fruit of the pineapple plant

DURKEE meat tenderizer has BROMELAIN

Papai n Its utility is in breaking down the tough meat fibers and has been utilized for thousands of years in its native South America. It is sold as a component in powdered meat tenderizer available in most supermarkets.

The cheap meat tenderizer had PAPAIN

This is an enzyme called

CATALASE

It’s active site

The substrate enters the ezyme’s active site

Enzymes are specific to the molecule with which they attach (substrate)

Enzyme molecule it attaches with

Stages of an enzyme-catalyzedreaction:

catalase

H2O2

Stages of an enzyme-catalyzedreaction:

catalase

H2O2

Stages of an enzyme-catalyzedreaction:

Stages of an enzyme-catalyzedreaction:

catalase

H2O

O2

Energy released

Energy released

Energy released

Energy released

Enzymes are affected by environmental factors: ex. pH

Energy o

Beyond that temp, speed of reaction drops:

Enzymes do have optimal pH:

Improper pH disrupts bonds in the protein

…remember, enzymes are PROTEIN

Enzymes are affected by environmental factors: ex. temperature

Enzymes are affected by environmental factors: ex. too cold

Enzymes slow down

They cannot

Enzymes are affected by environmental factors: ex. amount of heat

Acceptable temperature… PERFECT

Too hot… DENATURED

hmmm… WHAT would that do to the active site?

Too hot… DENATURED

Enzymes do have optimal temperatures:

heat disrupts bonds in the protein

…remember, enzymes are PROTEIN

Sometimes enzymes require nonprotein “helpers” Molecules that are bound to the active site

CoEnzymes

“A cell is not just a bag of chemicals with thousands of different kinds of enzymes and substrates wandering about randomly.”

Control of metabolism-

Chaos would result if all of a cell’s metabolic pathways were open at the same time… chemical reactions must be regulated

Cattle-ist