Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all...

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Enzymes Proteins in Action

Transcript of Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all...

Page 1: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

EnzymesEnzymes

Proteins in Action

Page 2: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Enzymes are ProteinsEnzymes are Proteins

Most enzymes are globular proteins.

Like all proteins, enzymes are made up of chains of amino acids.

Each enzyme has a specific shape in order to carry out its function.

Page 3: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Enzymes are catalystsEnzymes are catalysts

Catalysts are substances that lower the activation energy of a chemical reaction.

Enzymes make it easier to put together or take apart molecules.

Enzymes are specific. Each enzyme does only one kind of job.

Enzyme activity is regulated by the molecules they catalyze, or by other molecules.

Page 4: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Activation EnergyActivation Energy

Catalysts reduce the energy needed to carry out a reaction.

Page 5: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Enzyme StructureEnzyme Structure

An enzyme has an active site, into which fits a substrate, like a key into a lock.

Page 6: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Enzyme FunctionEnzyme FunctionThe substrate fits

into the active site in the enzyme.

The active site changes shape as it forces the reaction to take place.

The product is released, and the

active site returns to its original shape.

Page 7: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Metabolism and EnzymesMetabolism and Enzymes

Many biological functions, including metabolism, are enzyme driven, and may involve multiple

enzymes.

Page 8: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Enzyme RegulationEnzyme Regulation

Feedback loops often regulate enzyme reactions. For example, the product of a reaction may

inhibit one enzyme in the reaction.

Page 9: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Allosteric InhibitionAllosteric Inhibition

The regulator molecule changes the shape of the active site.

Page 10: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Competitive InhibitionCompetitive Inhibition

A molecule with a shape similar to the substrate fits into the enzyme’s active site. Some poisons work this way.

Page 11: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Reaction speedReaction speed

The speed of an enzyme-catalyzed reaction depends on:

temperature

pH

salinity

concentration of the substrate

concentration of the enzyme

Page 12: Enzymes Proteins in Action. Enzymes are Proteins Most enzymes are globular proteins. Like all proteins, enzymes are made up of chains of amino acids.

Enzyme SpecificityEnzyme Specificity

Each enzyme carries out one job, and one job only.

The lock-and-key fit between substrate and enzyme allows the enzyme to fit only certain substrates.

Any one enzyme will either put molecules together or break them apart. The same enzyme won’t do both.