HNF 461 1st Edition Lecture 30 Outline of Last Lecture I Amino Acid Catabolism a Transamination b Deamination II Amino Acids and the TCA Cycle III Urea Cycle IV Production of Urea V Urea Cycle and Ammonium VI Amino Acid Metabolism in Various Tissues a Muscle b Kidney c Brain Outline of Current Lecture I Protein Requirements II Protein Turnover III Protein Quality IV Complementary Foods V Evaluation of Protein Quality a AAS b PDCAAS c PER VI Nutrition Fact Labels Current Lecture Protein Requirement and Turnover Dietary Protein Quality 1 Protein Requirements a Need 20 21 amino acids for protein synthesis These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute b Dietary dispensable amino acids are required for metabolic functions c The amount of indispensable amino acids required depends on the amounts of dispensable amino acids in the diet i Methionine indispensable cysteine the amount of cysteine in the body determines if you need more or less methionine intake 2 Protein Turnover a Synthesis i Insulin and growth hormone promote N retention protein synthesis b Catabolism i Glucocorticoids glucagon and epinephrine promote protein catabolism break down c Adult humans synthesize and degrade 200 300 g protein day but only intake 50100 g day i A lot of recycling of proteins occurs in the body d Resting Metabolic Rate 60 of total energy expenditure i 10 25 of this 60 will be used for protein turnover 3 Protein Quality a Complete or high quality proteins contain all the amino acids b Incomplete proteins lack amino acids 4 Complementary Foods a Eat foods together so that one food will have an amino acid that another food lacks 5 Evaluation of Protein Quality a AAS Amino Acid Score Determines the amount of amino acids in a food compared to a reference protein b PDCAAS Takes into account the digestibility of a protein something can have a high concentration of protein but if the body can t digest it it is no use to the body c PER based on physiological weight gain 6 Nutrition Fact Labels a DV for protein 50 g if PDCAAS 100 b DV 65 g if PDCAAS 100 c For infants the DV is based on PER d Casein is the reference protein for the nutrition facts label
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