Proteins. 9/18/2015 Proteins: Organic compound –Made up of C, H, O, N and some with S –Proteins are made up of long chains of the repeating units called.

Proteins

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Proteins:

• Organic compound

– Made up of C, H, O, N and some with S

– Proteins are made up of long chains of the repeating units called amino acids.

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• There are 20 different types of amino acids that make up all proteins.

10 are essential to humans

10 Essential Amino Acids:

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• The 20 amino acids combine in different orders to make up different proteins

– Similar to the letters of the alphabet

• 26 different letters combine to make 500,000+ words

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Examples of foods rich in proteins:

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Foods which are the best sources of amino acids:

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S-T-E-A-K

S E T K T A S E

BloodHair protein-keratinMuscle proteinSkin protein-collagen

In other words…………….

You are what you eat!!!!!!!

Or this…………….

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Your choice………………….

How much protein should you eat/day?

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Multiply your weight in pounds by 0.4 to estimate how many grams of protein you need each day.

For example, a female who weighs 120 lbs would need about 48 grams of protein (120 lbs x 0.4 = 48 grams).

Food Grams of protein

3 oz of tuna 22 grams

3 oz of hamburger 21 grams

3 oz of chicken 21 grams

1 cup yogurt 11 grams

2 Tbsp peanut butter 8 grams

1 cup of milk 8 grams

1 egg 7 grams

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Function of Proteins:

• Overall job of proteins is to:

–Build new cells

–Repair damages to our tissues and cells

–Maintain our cells

–Help digest our food

–Regulate all cellular reactions

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• Proteins can be divided into two main types:

1. Structural Proteins:• They build and support our tissues

Examples of proteins:

Collagen…………………skin

Keratin……………………hair

Actin and Myosin………….human muscles

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• 2. Functional Proteins:

They perform specific functions within our bodies.

Example:

Enzymes…speed up chemical reactions like digestion

Insulin….transports glucose into cells

Antibodies….destroy bacteria and viruses

Hemoglobin…transports oxygen to cells

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• Amino acids bond together into chains with peptide bonds

• A type of chemical bond

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lysine Amino acid

Dipeptide

Tripeptide

Polypetptide

Peptide Bond

• All proteins have a very unique 3-D shape

– If 3-D shape is altered the protein will be damaged.• Extreme cold to collagen…………Frost bite• Extreme heat to collagen…………3rd degree

burn

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Frying an egg:

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Egg White: 10% protein

Yolk:15% protein

Levels of organization of a protein:

• 1st: Primary structure• Proteins are made in a linear shape

–Straight line

• A specific chain of amino acids is put together in the correct order according to DNA’s code

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One single change…

Amino Acid Sequence

Normal Sickle  

 -Threonine – Proline – Glucine – Glucine

-Threonine– Proline – Valine - Glucine

• 2nd: Secondary Structure• The chain of amino acids becomes:

– Coiled– Pleated– A spiral

– Shape held in place with weak Hydrogen bonds.

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• 3rd: Tertiary Structure– The amino acid chain gets a 3-D shape– Each type of protein has its own 3-D shape– If shape is altered the protein can not function

right.

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• 4th: Quaternary Structure

– This level is achieved when two protein chains bond together to create a new protein.

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Enzymes:

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-are catalyst-they are complex proteins that speed up all chemical reactions with our bodies.

Enzymes are responsible for:-cell respiration-photosynthesis-Protein synthesis-Digestion

Enzymes control every reaction

within our bodies.

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• Enzymes are substrate specific.

• Substrates are substances enzymes act upon like specific

types of food.

• Enzymes are specific types proteins. Therefore enzymes have specific 3-D shapes.

• For each substrate/substance there is only one enzyme that can act upon it.

Take the example of digestion:

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Enzymes make the reaction of digestion occur 10 million times faster than it would without the enzymes.

Digest candy bar with enzymes….20 min to 2 hours

Digest same candy bar without enzymes….100 years

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Substrate: Substance that an enzyme breaks down or acts upon. Ex: Our candy bar

Due to their specific 3-D shape an enzyme can only act upon one type of substrate.

There are different enzymes to break down the peanuts, the chocolate, the creamy filling, etc…..

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• Enzymes in the human alimentary canal and what they digest:

Enzyme SubstrateAmylase StarchMaltase MaltoseSucrase Sucrose

Lipase Lipids/Fats

Protease / peptin Proteins

The name of enzymes end in the suffix “ASE”.

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Enzymes follow the lock and key hypothesis:

For every type of substrate there is only one type of enzyme to break it down.

Just like there is only one specific key which fits into a specific type of lock.

Enzyme animation

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Let’s take a milk break…..

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Contains galactose and lactose sugars

Lactase

It’s a disaccharide

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-The specific 3-D shape of an enzyme is called the active site.

-point on the enzyme that “fits” around

or into the substrate.-point where the substrate is broken.

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-Enzymes are not altered or used up during a reaction.-Enzymes can be used over and over again.

Hyperlink

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How environmental factors affect enzymes:

Denaturing of enzymes:-extreme heat or coldness, and strong acids

or bases can alter the shape of the active site making it less effective. (breaks the hydrogen bonds holding the 3D shape in place).

-this is called the denaturing of the enzyme

FrostbiteHyperlink

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Coenzymes:

-Vitamins and minerals can bond to the enzyme and increase the rate of its

function.

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-Certain drugs can bond to the enzyme and block the active site rendering it useless for doing its real job.

Example: The drug marijuanacontains the chemical THC. THC temporarily bonds to enzymes in our brain cells causing them to notfunction correctly thus causing the temporary feeling of being “high”.

Competitive Inhibitors: