Protein Structure 1 Primary sequence of amino acids 02 26 2015 Determines shape 2 Secondary coiling and folding 3 Tertiary 3 D shape Determines function 4 Quaternary 3 D combining all polypeptides Protein Breakdown Denaturation in 3 D shape change o What causes it pH Acid or Alkaline Heat Alcohol Agitation Structure and Mechanical Functions 1 Collagen the most abundant protein in the body that exists in our skin bone hair and connective tissue 2 Keratin Dense protein that exists in our hair and nails 3 Motor proteins Used to turn energy into mechanical work exists in our muscles for muscle contraction 4 Enzymes All enzymes are proteins but not vice versa ex Lipase Sucrase etc 5 Hormones Chemical messengers formed in the body for effect elsewhere ex Insulin Leptin etc 6 Immune Function Antibodies blood proteins made by body immunoglobin 7 Fluid Balance proteins in blood maintain fluid levels ex albumin 8 Acid Base Balance Proteins are buffers can either donate or accept H to maintain stable blood pH levels 9 Transport Channels and pumps cell membranes Carriers Transport material in blood ex Lipoproteins Digestion of Protein Mouth Crushed and moistened Stomach begins digestion Small Intestine Hydrochloric Acid HCI that uncoils protein and activates pepsin Pancreatic and intestinal proteases and peptidases complete digestion Enzymes o Trypsin Chymotrypsin Carboxypeptidase Peptidases Absorption Amino acids are absorbed into the bloodstream Travel to liver which NH2 group is removed Deamination beings breaking some peptide bonds and activates break tri and di peptides into amino acids Becomes NH3 ammonia and converted again to urea Urea excreted by the kidneys Proteins Role as Energy Source Most protein in body used for protein synthesis Body will use protein to provide energy or make glucose if carbohydrate or fat are not available Provides 4 kcal gram Excess intake of dietary protein may be stored as fat Protein Nitrogen Balance Nitrogen from protein is excreted Can measure to determine protein adequacy Nitrogen balance intake output If Positive value Body is adding protein ex pregnancy If Neutral value Body s protein needs are in equilibrium ex healthy person If Negative value Body is losing protein e extreme dieting sever illness etc Recommended Protein Intake RDA usually used 0 8 grams per kilogram of body weight for adults Who has greatest need o Infants children pregnant and breastfeeding women etc o Clinical Burns surgery etc Daily value 50 grams of protein per day AMDR 10 35 of total kilocalories from protein How much do we eat Usually eat 15 kcal from protein Protein in Food Complete Proteins Supply all essential amino acids Animal proteins soy protein quinoa Incomplete Protein Low in one or more essential amino acids Mostly are plant proteins Whey Protein Complete Protein Found in dairy products Easily digestible Soy Protein Complete Protein Made from soybean Can contain fiber Average protein per food group Meat 7 grams ounce Dairy 8 grams cup Vegetables 2 grams cup Fruit no protein Whole Grains 6 grams cup Other grains 3 grams cup Measuring Quality of a Protein Biological Value Determines how much nitrogen from a food s protein is used by the Eggs have BV of 100 and we compare every food source to the BV body of eggs Whey 104 Milk 91 Casein 77 Soy 74 Protein Digestibility Corrected Amino Acid Score PDCAAS The value 1 is the highest Casein Eggs Soy Whey Protein and Amino Acid Supplements Pros and cons to use of supplements Safety Commonly include whey protein May increase protein synthesis slightly but not enough to improve Surplus of protein must be metabolized adding burden to kidneys athletic performance to excrete excess nitrogen Beneprotein 6 grams protein per 7 grams of powder Myoplex Whey Protein Powder 23 grams protein per 30 grams of powder Boost High Protein 15 grams per 8 ounces of protein Metabolism 02 26 2015 Energy Source of cells Chemical energy in the bonds of carbohydrates fat and protein Food energy to cellular energy Stage 1 Digestion absorption transport Stage 2 Breakdown of molecules Stage 3 Transfer of energy to a form cells can use Metabolism https www youtube com watch v wQ1QGZ6gJ8w Catabolic Reaction Chemical reactions that result in breaking down of body compounds large molecules are broken into smaller ones Catabolic reactions release energy Anabolic Reaction Chemical Reactions that result in building up of body compounds creation of larger molecules from smaller ones All anabolic reactions involved doing work and energy provided by ATP ATP High energy compound Provides energy to muscles enzymes Energy from Carbohydrates Glycolysis the process of splitting sugar Location Cytosol Start with glucose 6 carbons in its structure Split into 2 pyruvates 3 carbons in its structure Transfers electrons to co enzyme NAD Produces some ATP Pyruvate to acetyl CoA o Releases Carbon Dioxide o Transfers electrons to co enzyme NAD Lipid Catabolism Catabolism Adipose tissue is broken down and triglycerides are released as fatty acids which are absorbed by cells Energy from Fats Location inside mitochondria Fatty acids get there with help from the protein carrier carnitine Beta oxidation o Breaks apart fatty acids into acetyl CoA o Transfers electrons to co enzymes o Uses ATP Energy from Protein Amino Acids can Convert to pyruvate Convert to acetyl CoA Convert to a compound in the TCA cycle Entry point depends on side chain TCA Cycle Located in the mitochondria Acetyl CoA 2 C goes through cycle and a series of reactions occur The TCA cycle produces CO2 co enzymes NAD FADH and ATP Electron Transport Chain ETC Located in the mitochondria Co enzymes donate electrons to make ATP The ETC produces ATP and water Feasting Excess intake from all macronutrients Fat storage is promoted Fasting Inadequate intake of macronutrients Glycogen used first glucose needed for the brain Energy Balance 02 26 2015 1 Energy In Everything we take in food and beverages 2 Energy Out Resting energy expenditure BMR RMR 60 65 on BMR o Factors that affect the BMR Age height growth body composition gender fever stresses environmental temperature fasting starvation malnutrition hormones gender smoking caffeine and sleep Physical Activity 25 35 of energy Non Exercise Activity Thermogenesis NEAT Thermic effect of food TEF 3 A Word about Metabolism What Metabolism isn t Some process in your body that is either fast or slow What Metabolism is How much energy your body needs to perform vital life