Amino acids

amino acid is building block of amino acid.

1. AMINO ACIDS Building blocks of protein Mrs. Praveen Garg VITS College, Satna

2. INTRODUCTION Amino acids are organic compounds that combine to form proteins.  Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. Amino acids contain amine and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen, although other elements are found in the side chains of certain amino acids. Amino acids can also be used as a source of energy by the body.

3. The human body uses amino acids to make proteins to help the body. Break down food Grow Repair body tissue Perform many other body functions

4. Arginine - Arg – R Lysine - Lys – K Aspartic acid - Asp – D Glutamic acid - Glu – E Glutamine - Gln – Q Asparagine - Asn – N Histidine - His – H Serine - Ser – S Threonine - Thr – T Cysteine - Cys - C Tryptophan - Trp – W Tyrosine - Tyr – Y Methionine - Met – M Alanine - Ala – A Isoleucine - Ile – I Leucine - Leu – L Phenylalanine - Phe – F Valine - Val – V Proline - Pro – P Glycine - Gly - G TYPES OF AMINO ACIDS The 20 most common amino acids in proteins are listed with their three letter and one-letter codes:

5. ESSENTIAL AMINO ACIDS Essential amino acids cannot be made by the body. As a result, they must come from food. Example: Histidine , isoleucine , leucine , lysine, methionine , phenylalanine, threonine , tryptophan, and valine . NONESSENTIAL AMINO ACIDS Nonessential means that our bodies produce an amino acid, even if we do not get it from the food we eat. Example: Alanine , arginine , asparagine , aspartic acid, cysteine , glutamic acid, glutamine, glycine , proline , serine, and tyrosine. CLASSIFICATION Amino acids are classified into two groups:

6. They can be classified according to the core structural functional groups' locations as alpha-(α-), beta-(β-), gamma-(γ-) or delta-(δ-) amino acids. Other categories relate to polarity, pH level, and side chain group type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur, etc.). 

7. Classification Based on Polarity Non polar amino acids: They have equal number of amino and carboxilic group. These are hydrophobic and no charge on the R group. Example: alanine , valine , leucine , isoleucine , phenyl alanine , glycine , tryptophen , methionine and proline .

8. Polar amino acid with no charge: They do not have any charge on R group. They help in participate in hydrogen bonding of protein structure. Example: serine, threonine , tyrosine, cysteine , glutamine, aspargine .

9. Polar amino acid with positive charge: They have more amino groups as compared to carboxyl groups making it basic. Example: Lysine, Arginine , Histidine

10. Polar amino acid with negative charge: They have more carboxilic group than amino group making them acidic. Example: Aspartic acid, Glutamic acid

11. Acidic amino acids: These contain one amino and two carboxilc group. Example: Aspartic acid, glutamic acid Basic amino acids: These contain an additional basic such as amino group, guanidine, imidazole . Example: Lysine, Arginine , Histidine Neutral amino acids: These contain one amino and one carboxilic group. Example: Glycine , Alanine , etc. Classification Based on Acid/Base

12. ZWITTER ION A zwitterion , also called an inner salt, is a molecule that contains an equal number of positively and negatively charged functional groups. The example of zwitter ion is amino acid that contain -COOH and –NH 2 group in same molecule. In aqueous solution, -COOH group loses a proton ( H + ) to form a carboxylate (-COO - ) ion while –NH 2 group gains a proton to form –NH 3 ion, thus they exist as a dipolar ion at pH 7. Such a ion is called zwitter ion.

13. Acidic solution Neutral solution Zwitter ion Alkaline solution Amino acids are amphoteric molecule, they can donate or accept protons and act like as acidic and basic.

14. PROPERTY OF AMINO ACIDS Physical Properties: Amino acids are colorless, crystalline solid.  They are soluble in water, slightly soluble in alcohol and dissolve with difficulty in methanol, ethanol, and propanol . R-group of amino acids and pH of the solvent play important role in solubility. All amino acids have a high melting point greater than 200 o All amino acids (except glycine ) are optically active. Amino acids can connect with a peptide bond involving their amino and carboxylate groups. A covalent bond formed between the alpha-amino group of one amino acid and an alpha-carboxyl group of other forming -CO-NH-linkage.

15. Chemical property Decarboxylation : In this process, amino acids produce amines. Example: Histidine Histamine + CO 2 Tyrosine Tyramine + CO 2 Glutamic acid Gamma aminobutyric acid + CO 2 Tryptophen Tryptamine + CO 2 , Due to –COOH group

16. 2 . Reaction with ammonia: The carboxyl group of dicarboxilic amino acids react with NH 3 to form amide. Aspartic acids + NH 3 Asparagine Glutamic acids + NH 3 Glutamine 3. Salt formation: Amino acids form salts (- COONa ) with bases and form esters (-COOR) with alcohols.

17. Due to – NH 2 group 1. Reaction with Sanger reagent: 1-Fluoro-2,4-dinitrobenzene (commonly called Sanger's reagent, dinitrofluorobenzene , DNFB or FDNB) is a chemical that reacts with the N-terminal amino acid of polypeptides and produce yellow color derivatives 2,4 dinitrobenzene (DNB).

18. 2. Edmann reaction: An uncharged peptide is reacted with phenylisothiocyanate (PITC) at the amino terminus under mildly alkaline conditions to give a phenylthiocarbamoyl derivative (PTC-peptide). 

19. 3. Nin hydrin reaction: Ninhydrin  reacts with the α-amino group of primary amino acids producing ' Ruhemann's purple'. The chromophore formed is the same for all primary amino acids. 

20. Functions of Amino acids In particular, 20 amino acids are crucial for life as they form peptides and proteins and are known to be the building blocks for all living things. The linear sequence of amino acid residues in a polypeptide chain determines the 3D- configuration of a protein, and the structure of a protein determines its function. Amino acids are essential for the health of the human body. They largely promote the production of hormone. Structure of muscles  Human nervous system’s healthy functioning  The health of vital organs. Normal cellular structure

21. The amino acids are used by various tissues to synthesize proteins and to produce nitrogen-containing compounds (e.g., purines , heme , creatine , epinephrine), or they are oxidized to produce energy. THANK YOU