Enzymes

•Enzymes are Proteins•Enzymes are Catalysts- substances that speed up reactions without being altered in the process•Enzyme names end in “ase”

Chemical Reactions and Energy

• During chemical reactions bonds are broken and formed – energy is released or absorbed

• Chemical reactions that release energy often occur on their own, or spontaneously.

• Chemical reactions that absorb energy will not occur without a source of energy.

The Direction of Spontaneous Reactions (and what it takes to go the other way)

Where do we get Energy from?

• Every organism must have a source of energy to carry out the chemical reactions it needs to stay alive.

• Plants get their energy by trapping and storing the energy from sunlight in energy-rich compounds.

• Animals (Humans) get their energy when they consume plants or other animals.

Activation Energy• Every Chemical reaction – even the ones that

release energy and occur on their own need a push – something to get going

• Activation energy is the energy required to get going, to get a reaction started

Enzymes lower the Activation Energy

Enzymes speed up the reaction

Enzymes bind to substrates at their active site (lock and key model).

Substrate(s) – reactants of the chemical reaction

1 Enzyme – 1 substrate – 1 chemical reaction

A Fit between and enzyme and a substrate is critical and precise

How enzymes work

ENZYME DEFICIENCY AND HEALTH

Most genetic disorders are due to a deficiency in enzyme function.

This archival photo shows three children with the enzyme deficiency that causes phenylketonuria.

PKU test for newborns A phenylketonuria (PKU) test is done to check

whether a newborn baby has the enzyme needed to use phenylalanine in his or her body. Phenylalanine is an amino acid that is needed for normal growth and development. If a baby's body does not

have the enzyme that changes phenylalanine into another amino acid called tyrosine, the phenylalanine level builds up in the baby's blood and can cause brain damage, seizures, and mental deficiencies.

Enzyme Activity is Often Regulated

Feedback inhibition - a common form of enzyme regulation in which the product inhibits the enzyme.

When you have enough product you want to stop the reaction – productinhibits enzyme.

INHIBITION: NON-COMPETITIVE-an inhibitor binds to a site other than the active site which causes a change in the active

site

INHIBITION: COMPETITIVE- an inhibitor binds to the active site preventing the enzyme from binding to

the substrate

Brain Teaser

You have 10 locked doors and only 1 key that unlocks all the doors. It takes 1 min to unlock each door.

We are going to 'measure' how efficient you are by counting the unlocked doors/time.

Efficiency: 10 doors in 10 min

You find 1 more key and get a friend to help you.

Efficiency: 10 doors in 5 min

You recruit a total of 9 friends with keys to help you.

Efficiency: 10 doors in 1 min

Your friends bring their friends, and they bring their friends. You end up having 20 people with 20 keys.

Efficiency: 1 min, there are only 10 doors.

Enzymes

PART 2

Enzymes Part II

• Enzymes are proteins and have a specific shape

• Shape of Proteins can be affected by different environmental factors – temperature, pH, solute concentration, etc.

• If the shape is disrupted – the enzyme will not work

Enzyme Shape determines Enzyme specificity

In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site. The enzyme is the lock, and the reactant is the key.

+ ↔ ↔ +

Enzyme Shape• The shape of an enzyme is very important because

it has a direct effect on how it catalyzes a reaction.

• An enzyme’s shape is determined by the sequence of amino acids in its structure, and the bonds which form between the atoms of those molecules.

• Different types of enzymes have different shapes and functions because the order and type of amino acids in their structure is different.

The rate of enzyme-catalyzed reactions depends on several factors. What are some of these?

All enzymes work best at only one particular temperature and pH: this is called the optimum.

Factors that affect the rate of a reaction include: substrate concentration temperature

Different enzymes have different optimum temperatures and pH values.

pH enzyme concentration

surface area pressure.

Enzymes - Activity• Temperature and pH effect enzyme action

Enzymes - Activity• Temperature and pH effect enzyme action

The acidic (pH <4) and hot (>80°C) springs in Yellowstone National Park contain LIFE

Ice contains LIFE

“Weird” Life forms – extreme conditions

Life at Extreme conditions means that enzymes in these organisms can work at extreme conditions

Taq Polymerase – an enzyme isolatedfrom a microbe living in hot springs.

Its discovery has revolutionized Science: Biology, Medicine, Forensics

PCR – Polymerase Chain Reaction