Proteins

Protein Made of amino acids Amino acids are the building blocks of protein- they are organic acids Contain nitrogen – sets them apart from lipids and carbohydrates (prefix amine means contains nitrogen). Each amino acid has side chains that gives it its identity

The 20 Amino Acids What do they have in common? All contain Nitrogen All contain Carbon, Hydrogen, and Oxygen All have a carboxyl group

Essential / Non-Essential Asparagine Tyrosine Serine Valine Proline Tryptophan Glycine Threonine Glutamine Phenylalanine Glutamic acid Methionine Cysteine Lysine Aspartic acid Leucine Arginine Isoleucine Alanine Histidine Non-Essential Essential Essential – amino acids the body does not produce. Must obtain through diet. Non-Essential – amino acids produced by the body.

Amino Acids The 20 amino acids are like letters and form different sequences The number of protein combinations is greater than the number of English words (more than 100,000 unique proteins) A single human cell may contain 10,000 different proteins

Protein Shape Proteins are extremely large molecules with complex shapes Shape determines function Artist renderings of 6 different protein molecules. Each contains thousands of amino acids.

Protein Uses Creating DNA Catalyzing reactions in cells Transporting other molecules Structurally supporting cell walls Immune responses (many proteins fight disease) Red blood cells (hemoglobin) – transport oxygen throughout the body. Involved in some way in virtually every cellular process

Dehydration Synthesis The carboxyl (COOH) group on one amino acid reacts with the amide group (NH2) on the other. Removal of water creates a C-N peptide bond. All amino acids are connected via peptide bonds.

Hydrolysis The reverse of dehydration synthesis, hydrolysis breaks the peptide bond and restores the original amino acids.

Denaturation Proteins do not dissolve in water The change in a protein’s shape brought on by Heat acids or bases alcohol They unfold.

Sources of Protein Complete Proteins (all 20 amino acids) All meats and animal products- eggs, cheese, milk Fish Legumes - alfalfa, clover, peas, beans, lentils, mesquite, carob, soybeans (tofu and soy products), peanuts, tamarind Buckwheat Quinoa Incomplete proteins Nuts Some grains / rice

Digestion Proteins begin their digestion in the stomach, where an enzyme called pepsin begins to break down peptide bonds. Smaller groups of amino acids move into the small intestine where they are broken down into single amino acids where they are absorbed. Amino Acids are circulated through blood, where they are used for many different functions in the body.

Digestion Some more easily digested than others Animal proteins complete proteins easy to digest and absorb - 90% Legumes Also complete but harder to digest - 80% Grains/ plants Incomplete Vary in ability to digest - 60-90%

Role of proteins Support new tissue growth Hemoglobin – red blood cells Fluid and electrolyte balance – cell transfer

Hormones to regulate body functions Immune system – large proteins act as antibodies to protect against disease Provide energy, when carbs and fat in short supply – your body does not go to protein for energy unless it has to, as proteins are primarily used to maintain a multitude of functions in the body.