PROTEIN

Somatic Protein: Function Cellular growth, maintenance. Hormones Acid base regulation Water regulation Enzymes Transporters Antibodies Neurotransmitters

Dietary Protein: Function Use only for the previous functions Energy. Protein is used for energy when Glycogen and fat stores are low (starvation). Rigorous, continuous exercise (ultramarathon). When carbohydrate intake is inadequate. When caloric intake is inadequate. Your body uses protein as energy as a LAST resort to give your brain glucose. Using protein as an energy source is called “amino acid wasting.”

Dietary Protein Requirements For inactive individuals, RDA is .8g per kg For moderately active individuals 1g per kg For very active individuals (training athletes) the requirement is 1.2 - 2g per kg depending on type of exercise. The average woman should consume 50g per day. The average man should consume about 60g per day. Calculate your dietary protein intake.

Amino Acids Amino acids. Are the building blocks of a protein. Types Essential. Cannot be made by the body. Must be consumed in food products (plant and animal). Non-essential. Can be made by the body from other amino acids, or fats, carbohydrate and N. Conditionally essential. Is dependent upon the intake and complete conversion of the essential amino acid that is its precursor.

Chemical Structure of an Amino Acid

How Amino Acids Compare

Protein Synthesis Proteins are made by condensation of amino acids together.

Protein Synthesis Protein Synthesis starts in the nucleus Production of a protein actually occurs on a ribosome of the rough endoplasmic reticulum in each cell.

Structure Dictates Function For a protein to function correctly all following criteria have to be met: All amino acids have to be present. Amino acids must be in the correct sequence as dictated by DNA/MRNA instructions. Protein has to be in the correct structure with other compounds that are necessary. If all the following criteria is not met, the protein will either not be made, or the protein will not function properly.

Human Insulin: Amino Acid Sequence

Protein Denaturation Proteins can be metabolized, destroyed or rendered dysfunctional by denaturing. Components of denaturing Heat PH changes Extreme pressure Detergents and caustic solvents (bleach) Denaturing DIETARY protein will not affect it’s protein content. Denaturing SOMATIC proteins (fever, altered blood PH) can adversely affect body functions

Protein Quality Complete Protein: Contains all the amino acids in the proportion that humans require. Ex: all meats and dairy products. Soy is close. Incomplete Protein: Does not contain all essential amino acids. Ex: grains, vegetables, legumes. Mutual supplementation: Eating two complimentary proteins together as to supply all the amino acids Complimentary proteins. Food products which have amino acid profiles that compliment each other.

Legumes Nuts and seeds Legumes Vegetables Grains

Evaluation of Protein Quality PDCAAS. Protein Digestibility Corrected Amino Acid Scoring. PDCAAS are used to evaluate protein quality in many food products. To attain a score, the protein’s amino acid profile is compared against the amino acid requirements of preschool aged children and then corrected for digestibility. (Biological Value) Digestibility (Biological Value) is established by nitrogen retention studies conducted on humans.

Protein Turnover Nitrogen Balance: Nitrogen IN vs Nitrogen OUT Nitrogen equilibrium Positive nitrogen balance Negative nitrogen balance Deamination. The breaking off of nitrogen group so the remaining parts can be used for making non-essential amino acids, other proteins, glucose, fat, and neurotransmitters. A constant process in the liver. Ammonia is produced. Transamination. The transfer of the nitrogen group from one amino acid to a keto acid producing a new amino acid and a free keto acid. This process does not create ammonia.

Under consumption of protein. PEM. Protein-Energy Malnutrition Marasmus. Starvation Kwashiorkor. Protein malnutrition Both have similar and very different symptoms (look in text). However, both are harmful and eventually cause death if left untreated. For the average person, low protein can cause muscle wasting, fatigue, poor injury recovery, edema, and compromise the immune system.

Over consumption of protein Human body can handle 350 grams or more of protein without harmful effects as long as the nitrogen is being used. If nitrogen is not being used: Increased urination to rid excess nitrogen Increased kidney and liver work load Excess excretion of nitrogen may affect bone calcium. Increased urination can lead to dehydration Use of single amino acids is not advised.

Vegetarianism Chosen for religious, ethical, aesthetic, or experimental reasons. Three types: Ovo-Lactovegetarian: Will eat eggs and dairy Lactovegetarian: Will eat dairy products only Vegan: Will NOT eat ANY animal derived products. “Semi-Vegetarians” are NOT true vegetarians Vegans must use mutual supplementation or soybean products to fulfill protein needs. Vegans must take D and B12 supplements or received them from fortified foods. Vegans must be mindful to eat a varied diet to receive calcium, iron, and zinc.

Protein Quiz 1. Element found in protein, but not in carbohydrate or fat. a. Carbon b. Hydrogen c. Nitrogen d. Oxygen 2. The building blocks of protein a. Keto acids b. Amino acids c. Ammonia d. glyercol 3. The unraveling of a protein’s structure due to heat, acid, alkalinity or pressure. a. Denaturation b. Condensation c. Trans-amination 4. Incomplete proteins that complete each others amino acid profiles. a. mutual b. essential c. complimentary d. PDCAAS During construction of a specific protein, the body will replace a missing amino acid with another that is readily available True or False? Extra Credit: Identify 1 essential amino acid.