Downloaded 134 times
More Related Content
The proteins
- 1. Biochemistry for nurses:Unit 1 THE PROTEINS
- 2. Biochemistry for nurses:Unit 3 DEFINITION OF THE PROTEIN • The proteins are the more complex molecules in the living cells. • A human body has around 100.000 differents types of proteins. • A protein is a biological macromolecule composed by one or several peptides. • A peptide is a polymer (= chain) of amino acids (AA) linked between them by a peptide bond. •Protein = AA > 100; Peptide = 10 ≤ AA ≤ 100; Oligopeptide = AA ≤ 10 (including Tripeptide (AA = 3); Dipeptide (AA = 2))
- 3. Biochemistry for nurses:Unit 3 The amino acid The amino acid is the basic unity of the protein. The amino acid is composed by a carbone (C) on which is linked: • An amino group (NH2) • An acid group (COOH) • A variable chemical group (R) • A hydrogen (H)
- 4. Biochemistry for nurses:Unit 3 20 standard amino acids
- 5. Biochemistry for nurses:Unit 3 20 standard amino acids
- 6. Biochemistry for nurses:Unit 3 20 standard amino acids
- 7. Biochemistry for nurses:Unit 3 Amino acids abbrevation table
- 8. Biochemistry for nurses:Unit 3 The peptide bond • The amino acid (AA) molecules are linked each other one by peptide bonds. • A peptide bond is a covalent bond between the carboxylic group (CO) of one amino acid and the amino group (NH2) of another amino acid molecule. • The formation of a peptide bond releases a water molecule (H2O) = reaction of condensation. • The assembly of several AA molecules gives a peptide (AA ≤ 20) • The assembly of several peptides gives a protein (AA ≥ 20)
- 9. Biochemistry for nurses:Unit 3 The peptide bond
- 10. Biochemistry for nurses:Unit 3 Protein synthesis (= Transcription + Translation) • The protein synthesis has 2 steps: the transcription of the DNA into a mRNA, and the translation of the mRNA into a protein. •The proteins are assembled from amino acids according the informations provided by the RNA messenger.
- 11. Biochemistry for nurses:Unit 3 • The translation is the application of the genetic informations provided by the mRNA. The amino acids are free inside the cytoplasm before to be assembled to form the proteins during the translation step. •Translation = Ribosome + amino acids + tRNA + mRNA
- 12. Biochemistry for nurses:Unit 3 Essential and non-essential amino acids • An essential amino acid is an indispensable amino acid that cannot be synthesized by the human body: THEY ARE PROVIDED BY THE NUTRIENTS (FOODS) • A conditionally non-essential amino acid is an amino acid which becomes essential in some cases (premature baby). • A non-essential amino acid can be synthesized by the human body.
- 13. Biochemistry for nurses:Unit 3 The primary structure: • The primary structure corresponds to the amino acids sequence according the mRNA gene. • We see the primary structure only during a short time, i.e, during the elongation process of the protein synthesis. THE PROTEIN STRUCTURE
- 14. Biochemistry for nurses:Unit 3 The secondary structure: • The variable chemical groups (R) of the AA have differents properties: Hydrophobic, hydrophilic, charges (+) or (-) , -SH groups… Intramolecular chemical interactions: Hydrogen bonds, Disulfide bridges, Ionic bonds, hydrophobic and hydrophilic interactions… Alpha-helice and Beta-sheet structures
- 15. Biochemistry for nurses:Unit 3
- 16. Biochemistry for nurses:Unit 3 The tertiary structure: • The tertiary structure is the final form of the protein. • The function of the protein is strongly related to its final form (structure). • The final structure can be destroyed in case of a heating process or extrem pH = Denaturation process Biological function is lost!
- 17. Biochemistry for nurses:Unit 3 The quaternary structure: • In case of proteins composed by tertiary assembled subunits (Hemoglobin, Immunoglobin…)
- 18. Biochemistry for nurses:Unit 3 According their compositions: 1. Holoprotein = Protein composed only by amino acids. 2. Conjugated protein = protein composed by amino acids and by something else (carbohydrates: Glycoprotein, lipids: lipoprotein). Protein classification According their functions:
- 19. Biochemistry for nurses:Unit 3 What is an enzyme? • Enzymes are proteins produced in living cells. • Enzyme are biological catalysts = They speed up the rate of chemical reactions.
- 20. Biochemistry for nurses:Unit 3 What is an enzyme? • Enzyme are specific to a particular substrate (Key-Lock: sucrose-sucrase, maltose-maltase,…).
- 21. Biochemistry for nurses:Unit 2 The cytoskeleton The cytoskeleton is a dynamic protein structure: It is a skeleton and a musculature in same time for the cells. The cytoskeleton has the function to maintain the shape of the cell, to create a cell movement. It is involved in the cell division.
- 22. Biochemistry for nurses:Unit 3 Clinical correlation
- 23. Biochemistry for nurses:Unit 3 • The Alzheimer’s disease is a chronic neurodegenerative disease = a progessive destruction of the brain neurones over time until death. • Most often begins in people over 65 years. • It was first described in 1906 by the german psychiatrist and pathologist Alois Alzheimer. • The cause is almost unknown: The most probable hypothesis is a genetic anomaly. • No treatments stop or reverse its progression. • No medications or supplements decrease the risk factor. ALZHEIMER’S DISEASE (AD)
- 24. Biochemistry for nurses:Unit 3 AD is caused by 2 types of protein accumulation, Intra and extracellular, which cause plaques and tangles in the Brain. Disintegration of the microtubules accumulation = Tangles of Tau porteins Destroying the structure of the cell’s cytoskeleton = Death of the cell Intracellular: Anomaly of TAU proteins
- 25. Biochemistry for nurses:Unit 3 Accumulation Senile plaques Destruction of the surrounding neurones Extracellular: Anomaly of Amyloid proteins
- 26. Biochemistry for nurses:Unit 3 The Alzheimer’s disease slowly invades the different areas of the brain and gets worse over time. The disease causes progressively visibles symptoms according the affected brain areas.