2. ILO 1-Explain the chemical structure,classification, and properties of amino acids and how peptides are formed. 2-Describe the order of protein organization. 3-Relate the structures of amino acids and proteins to their properties. 4-Describe the physical and chemical changes due to protein denaturation 5-state different classifications of proteins giving examples. 6-Explain protein folding and pathophysiological consequences of protein misfolding. 1-Explain the chemical structure,classification, and properties of amino acids and how peptides are formed. 2-Describe the order of protein organization. 3-Relate the structures of amino acids and proteins to their properties. 4-Describe the physical and chemical changes due to protein denaturation 5-state different classifications of proteins giving examples. 6-Explain protein folding and pathophysiological consequences of protein misfolding.

3. Amino acid structure Amino acid properties Protein structure Forces that stabilize protein structure Levels of protein organization Protein Classification Protein folding Protein misfolding Denaturation Outlines

4. Protein classificatio n Protein properties

5. + Protein Classification By :DR.Marwa Matboly

6. No Universal system for protein classification According to structureAccording to biological activitiesAccording to shape(axial ratio)According to solubility Protein classification

7. Classification according to structure Simple proteins Formed only of amino acids e.g. albumin, globulin Compound protein Proteins containing amino acids+ other group e.g. phosphoprotein, lipoprotein, Derived proteins Hydrolytic products Denaturation products

8. Simple proteins Albumin (serum albumin, lactalbumin, and ovalbumin) Some Globulins(serum globulins are glycoproteins not simple proteins)

9. Compound proteins Amino acids Other group (prosthetic) Compound=conjugated protein

10. Compound proteins Contain phosphate attached to serine or theronine residues f the protein. e.g. casein of milk Phosphoproteins They are proteins usually basic proteins (histones) combined to nucleic acids. DNA of chromosomes is negatively charged, combine with the positively charged basic protein e.g. histones. Nucleoproteins

11. Compound proteins Contain lipids e. g. plasma lipoproteins: LDL: low density lipoproteins HDL: high density lipoprotein Lipoproteins Contain a metal: e. g. Iron containing transferritin Copper containing ceruloplasmin Zinc containing carboxypeptidase Metalloproteins Contain a colored prosthetic grop:protoporphyrin Eg Hemogloin Chlorophyl protein hemocyanin Chromoproteins

12. Compound proteins Protein covalently linked to short branched carbohydrates Glycoproteins Protein covalently linked to large carbohydrates part. Proteoglycan =glycosaminoglycan

13. Derived proteins Hydrolytic products peptonespeptides Denaturatio n products Metaproteins Coagulated proteins

14. Classification according to biological value High biological value proteins Contain all essential amino acids required for synthesis of human tissue proteins. Proteins of animal origin: meat liver, milk, fish Some Plant Proteins(beans, lentils, potato) Low biological value proteins Lack one or more essential amino acids Most plant protein(zein of maize deficient in tryptophan and lysine) Non digestible scleroproteins; eg. Scleroproteins. Gelatin, produced by boiling of collagen

15. High biological value protein Low biological value protein

16. Classification according to shape Axial ratio>10 Fibrous protein Axial ratio<10 Globular proteins

17. Classification according to solubility Soluble in water; albumin Soluble in dilute salt solution; globulin Proteins soluble Scleroproteins which are fibrous proteins with structural and supportive functions, e.g. keratin Proteins insoluble in water or any neutral solvents

18. + Properties of proteins

19. Most abundant macromolecules in living cells Formed of C, H, N Nitrogen contents of protein is 16% Most proteins contain about 1% sulphur.

20. Proteins are amphoteric weak acidic groups Weak basic R groups Free NH2 Free COOH They act as an acid or base

21. Cytosolic proteins for colloidal solution(size 1- 200nm and have the same charge),and non dialyzable

22.  PI of protein=zwitter ion(dipolar ion) It is pH at which a protein carries net zero charge the protein is electrically neutral the protein will not migrate in electric field Protein will be precipitated

24. At pH <pI of the protein Protein is Positively charged. Protein migrate towards the cathode in electrophoresis. At pH >pI of the protein Protein is negatively charged Protein migrate towards the anode in electrophoresis.