MIDTERM: Lesson 2.1: Proteins and Amino Acids

Proteins

Comes from the Greek word, meaning “first rank of importance”.

Antibody

Exposure to proteins will stimulate ________ production.

Proteins > polysaccharides > nucleic acids > lipids

Degree of immunogenicity:

Proteins

These are macromolecules composed of polymers of covalently linked amino acids that are involved in every cellular process.

Amphoteric

Proteins that can bear positive and negative charges.

High dielectric properties

Their solubility is due to?

12% - 20%

They provide _______ of the total daily body energy requirement.

50% - 70%

Proteins is composed of ________ of cells’ dry weight.

Structural

Proteins that provide structural components

Collagen

What example of structural proteins is the tendons and cartilage?

Keratin

What example of structural proteins is the hair, skin, wools, and nails?

Contractile

Proteins that is responsible in the movement of muscles?

Myosin and Actin

Examples of contractile proteins.

Transport

Proteins that carry essential substances throughout the body?

Hemoglobin

What example of transport protein is responsible in transport of oxygen?

Lipoproteins

What example of transport protein is responsible in transport of lipid?

Albumin

What example of transport protein is responsible in transport of hormones?

Storage

Proteins that store nutrients

Casein

Storage proteins that stores proteins in milk

Ferritin

Storage proteins that store iron in the spleen and liver

Hormone

Proteins that regulate body metabolism and nervous system

Enzymes

Propteins that catalyze biochemical reaction in the cells

Sucrase

What enzymes catalyzes the hydrolysis of sucrose?

Trypsin

Proteins that catalyzes the hydrolysis of proteins?

Protection

Type of proteins that recognize and destroy foreign substances

Immunoglobulins

Example of protection proteins

Non-Ionized form of Amino Acid

Ionized form of Amino Acid

Proline

______ is for the flexibility of the hinge region of immunoglobulins

Amino Acids

The monomer unit of proteins.

Polymers

Since amino acids are the monomer units of proteins. Therefore proteins are?

Linking together monomers unit

Polymers are made by ___________________?

Condensation

Polymers are made by linking together monomer units.

This process is known as?

Hydrolysis

• Breaks polymers apart.

• The final product has a lower potential energy bond than the reactant.

Polypeptide Structure

A chain of peptide bonds is considered the backbone or structural framework or the protein.

Primary, Secondary, Tertiary, and Quaternary

Levels of Proteins Structure

Primary Sturcture

• Linear order of amino acids

• Every protein has a unique sequence or order of amino acids.

Secondary Structure

• Alpha helix and beta sheets, not likely to contain proline.

• Local folding of residues into regular patterns.

• Created by interactions of the polypeptide backbone.

Tertiary Structure

• 3 dimensional folded shape of the protein

• Global folding of a protein chain

Quaternary Structure

• More than one polypeptide chain interacting to form a single structure

• Higher-order assembly of proteins.

Non-Essential Amino Acids

• The body can synthesize these for itself.

• Food usually delivers these to the body but it is not essential for food to deliver these amino acids usually.

Essential Amino Acids

Cannot make on its own or cannot make sufficient amounts of these amino acids.

• Therefore, they are required in the diet.

Conditionally Essential Amino Acids

Sometimes a non-essential amino acid becomes essential.

Protein Denaturation

If change in protein structure causes it to lose function.

Peptidases

Split most of the dipeptides and tripeptides into single amino acids.

Histones

strongly basic proteins that are insoluble in ammonium hydroxide but soluble in water.

Globins

sometimes classed as histones but appear to be a separate group as they are not basic nor are they precipitated by ammonium hydroxide.

Biuret test

Violet, general test for proteins/peptides

Xanthoproteic test

• Tests tyrosine, tryptophan, phenylalanine

• Concentrated nitric acid, tests aromatic amino acids

Millon’s test

• Detects tyrosine in the phenolic group

• Composed of mercuric nitrate color red

Hopkins-Cole test

Detects tryptophan

Ninhydrin test

• Detects the free amino group

• Rheuman’s purple