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Enzymes - Level

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1. Enzymes - LevelI. Enzymes are proteins and have a 3D shape.

II. Enzymes turn the food we eat into energy and unlock this energy for use in the body.

III. Act as catalyst to accelerate a reaction. IV. Not permanently changed

in the process.

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1. EnzymesV. Enzymes are specific for what they

will catalyzeVI. Are reusableVI. End in – ase

a. Examples: -Sucrase -Lactase -Maltase

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1. Enzymes

VII. How do enzymes work?

a. Enzymes work by weakening bonds which lowers activation energy

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1. EnzymesVIII. How do enzymes function?

a. Enzymes attach to molecules called substrates, forming the enzyme-substrate complex:

i. The substrate is the molecule that the enzyme acts upon.

EnzymeSubstrate Joins

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1. Enzymeb. The substrate enters a specific location on the

enzyme known as the active site.

i. Active site: A restricted region of an enzyme molecule which binds to the substrate.

EnzymeSubstrate

Active Site

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1. Enzymesc. Induced Fit: A change in the shape of an

enzyme’s active site

i. Induced (started) by the substrate

ii. A change in the configuration of an enzyme’s active site.

Enzyme

Active Sitesubstrate

induced fit

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1. Enzymes

Enzyme may be used againEnzyme-

substrate complex

E

S

P

E

E

P

Reaction coordinate

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1. Enzymes

IX. What Affects Enzyme Activity?

a. Two factors:

1. Environmental Conditions

2. Enzyme Inhibitors

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1. Enzymes

1. Environmental Conditions: A . Extreme Temperatures are the most

dangerous.

i. High temps may denature (unfold) the enzyme.

B. pH (most like 6 - 8 pH near neutral)

C. Ionic concentration (salt ions)

1. EnzymesV. The pH scale is a measure of

the concentration of hydrogen ions (H+) in a solution. The scale runs from 0 – 14. Pure water has a pH of 7.

1. Basic solutions have pH values above 7.

2. Acidic solutions have a pH below 7.

• 3. Each number on the scale has 10 times the number of hydrogen ions as the number before it.

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1. Enzymes

2. Two examples of Enzyme Inhibitors:

a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site.

Enzyme

Competitive inhibitor

Substrate

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1. Enzymes

3. Two examples of Enzyme Inhibitors:b. Noncompetitive inhibitors: Inhibitors that do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn

alters the active site.

Enzymeactive site altered

NoncompetitiveInhibitor

Substrate

14http://www.youtube.com/watch?v=PILzvT3spCQ

1. Enzymes