Biochemistry Lecture 7 PDF

Biochemistry Amino Acids LECTURE (7) DR. El-Sawy 1  Biochemistry Amino Acids...

Biochemistry Amino Acids LECTURE (7) DR. El-Sawy 1  Biochemistry Amino Acids  Structural units of proteins Def :  Obtained from protein by acid, alkali or enzymatic hydrolysis. Number :  20 amino acid.  Each AA (except proline & hydroxyl proline) has: 1. COOH group. 2. NH2 group attached to α-carbon (α-amino acid). 3. Side chain (R) → characteristic for each A.A. General structure : 1. Chemical Classification. Classification 2. Nutritional Classification. 3. Metabolic Classification. DR. El-Sawy 2  Biochemistry Amino Acids According to fatty acids : Chemical Fatty acid Amino acid Structure Acetic acid CH3-COOH Glycine Alanine Phenyl alanine Serine Tyrosine Propionic acid CH3-CH2-COOH Cysteine Tryptophan Cystine Histidine CH3-CH2-CH2- Butyric acid Threonine Methionine COOH CH3-CH2-CH2- Valeric acid Arginine CH2-COOH Iso-valeric acid - Valine Isoleucine CH3-CH2-CH2- Caproic acid Lysine CH2-CH2-COOH Iso-caproic - Leucine acid Imino acid Contain NH Proline hydroxyl proline Di-carboxylic - Glutamic acid Aspartic acid (Acidic AA) Branched chain A.A = Valine , Isoleucine & leucine (VIL) DR. El-Sawy 3  Biochemistry Amino Acids According to number of amino & carboxylic groups : Valine Isoleucine Leucine Alanine Glycine Tyrosine. Serine Threonine NH2 group = Neutral AA COOH group Cysteine Cystine Methionine. Tyrosine Phenylalanine Tryptophan. Proline Hydroxy-proline  Arginine Basic NH2 group ˃  Histidine AA COOH group  Lysine. NH2 group ˂  Glutamic acid. Acidic AA COOH group  Aspartic acid. DR. El-Sawy 4  Biochemistry Amino Acids Essential Non-essential  Not synthesized in body.  Synthesized in body. Def  Must be taken in diet.  Must not be taken in diet. Deficiency  nutritional deficiency diseases. 1. Valine 1. Alanine 2. Isoleucine 2. Aspartic acid 3. Leucine 3. Glutamic acid 4. Lysine 4. Glycine ‫الباقي‬ 5. Arginine 5. Serine Example 6. Histidine 6. Cystiene 7. Methionine 7. Cystine 8. Tryptophan 8. Proline 9. Threonine 9. Hydroxyproline 10. Phenylalanine 10. Tyrosine 1. Glucogenic Ketogenic Mixed  Carbohydrate & Converted  Carbohydrate.  Ketone bodies. to ketone bodies.  Aromatic AA : (tyrosine , Phenyl  Leucine. Examples  All others. alanine & Tryptophan)  Lysine  Isoleucine.  Threonine. DR. El-Sawy 5  Biochemistry Amino Acids Reaction due to both NH & COOH group : Amino acids condense with each other by COOH group at one amino acid with of other amino acid to form peptide bond. If 3 amino acids condense together they form tripeptide and so on. DR. El-Sawy 6  Biochemistry Amino Acids  An 8-year-old African American boy was experiencing pain in the chest and back. He was taken to the hospital, where he was found to have anemia, splenomegaly, and his RBCs showed like sickles. A preliminary diagnosis of sickle cell anemia was made.  To validate the diagnosis, a small aliquot of his blood was subjected to electrophoresis to determine the identity of the hemoglobin in his erythrocytes.  Case result interpretation: In sickle cell anemia, glutamic acid (acidic amino acid) at position 6 in Hb β chain is replaced by valine (Neutral), meaning that the HbS will have one less negative charge overall compared with HbA. DR. El-Sawy 7  Biochemistry Amino Acids  A 37-year old female came to your clinic to discuss her plans for a new vegetarian diet. She heard from a friend about a new vegetarian diet that promised rapid weight loss. The diet consists of many leafy vegetables with no animal proteins at all. She is also planning of running a marathon within the year. After listening to her, you referred her to a nutritionist for further assistance and guidance. Essential amino acids must be taken in diet because they cannot be synthesized in body. DR. El-Sawy 8