1. UNIT 8 THE AMINO ACIDS

2. LEARNING OBJECTIVES  State the composition and describe the structure of amino acids.  Classify amino acids.  List essential, semi-essential and non- essential amino acids. 2

3. AMINO ACID  Principal source: hydrolysis of protein  Proteins: high molecular weight substances (found in all living tissues)  attached to the same α-carbon 3

4. R AMINO ACID STRUCTURE R OH C +H3N+H3N  O

5. BUILDING AN R GROUP CH 3 CH 2 H OH Glycine AlaninePhenylalanine Tyrosine With an H, glycine is the simplest amino acid Alanine with a methyl group is the next simplest. Phenylalanine arises when a phenyl group replaces an H on alanine’s methyl group Tyrosine evolves by adding an –OH group to the para position on the phenyl ring of phenylalanine

6.  Substances (found in all living tissues)  Upon Acid, base or enzymes catalyzed hydrolysis:  Broken into thousands of amino acids molecules  Most proteins produce approximately 20 different α- amino acids  Amino Acids - have both an amino & a carboxylic acid group attached to the same α-carbon 6

7. FUNCTIONS OF AMINO ACIDS 7 1. Building blocks of proteins 2. Specific amino acids give rise to specialized products:

8. FUNCTIONS OF AMINO ACIDS 8 2. Specific amino acids give rise to specialized products: TYROSINE forms thyroid hormones T3 T4 and melanin TRYPTOPHAN can synthesize a vitamin called niacin GLYCINE, ARGININE AND METHIONINE synthesize creatinine. GLYCINE and CYSTEINE helps in the synthesis of bile salts. CYSTEINE and METHIONINE are sources of sulphur.

9. LEARNING OBJECTIVES  State the composition and describe the structure of amino acids.  Classify amino acids.  List essential, semi-essential and non- essential amino acids. 9

10. Classification and Structure of Amino Acids 10 NeutralAcidicBasic Aromatic Heterocyclic Sulphur containing amino acids Alipathic

11. LEARNING OBJECTIVES  State the composition and describe the structure of amino acids.  Classify amino acids.  List essential, semi-essential and non-essential amino acids. 11

12. ESSENTIAL AMINO ACIDS 8 Amino Acids not Synthesized by the body & Therefore Must Be Taken in the Diet 1. Leucine 2. Isoleucine 3. Threonine 4. Tryptophan 5. Phenylalanine 6. Valine 7. Metheonine 8. Lysine 12 Mnemonic Pvt. Tim Hall 563 427 18 H – Histidine A – Arginine

13. ESSENTIAL AMINO ACIDS Leucine Isoleucine Threonine Tryptophan Phenylalanine Valine Metheonine Lysine 13 To Maintain The Proper Nitrogen Balance In The Body CHILD: Growth failure ADULT: decrease plasma protein and hemoglobin levels DEFICIENCY (1 or more)

14. SEMI-ESSENTIAL AMINO ACIDS  Histidine  Arginine 14 Synthesized partially by the body But not at the rate to meet the requirement in growing children, pregnant and lactating women

15. NON-ESSENTIAL AMINO ACIDS  Alanine  Aspartic acid  Serine  Proline 15 Can be synthesized by the body May not be required in the diet Derived from carbon skeletons of lipids and carbohydrates during metabolism or from the transamination of essential amino acids

16. Complete or Adequate Proteins Complete or Adequate Proteins: Animal Proteins- Supply all of the essential amino acids. Incomplete Proteins: Vegetable Proteins- Low in one or more of the essential amino acids ANIMAL PROTEINS SOURCETYPE OF CHONMISSING AA EggCompleteNone Milk (Dairy)CompleteNone Meat, FishCompleteNone

17. SOURCETYPE OF CHONMISSING AA WheatIncompleteLysine CornIncompleteLysine &Tryptophan RiceIncompleteLysine BeansIncompleteMethionine &Tryptophan PeasIncompleteMethionine VEGETABLE PROTEINS The two vegetable proteins are called complementary proteins. –Ex. Rice and Beans

18. Leu L -C-C-CONH 2 -C-CONH 2 -C-COOH-C-C-COOH -H -CH 3 -C-OH-C-SH -C-C-S-C PPro -C-C C N N + -C-C-C-C-NH 3 + -C- -C- -OH -C- N Central line Aliphatic Amide Acidic Imino, Circular Basic SulfurHydroxy Aromatic -C-C-C-N-C-N N + = C -C-C-C C -C-C-C C C -C C C C HN C-COOH  -C-C OH Gln Q Asn N Asp D Glu E Phe F Arg R Lys K His H Gly G A A Ala V Val I Ile Y Tyr Ser S Thr T Met M Cys C Amino Acid Subway Map Trp W Non-polar Polar This is NOT a metabolic pathway

19. POLAR NON- POLAR TyrHis Gly AcidicNeutralBasic Asp Glu Gln Cys Asn Ser Thr Lys Arg Ala Val Ile Leu Met Phe Trp Pro Classification of Amino Acids by Polarity

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