Protein Structure Danilo V. Rogayan Jr.

Transcription

1 Protein Structure Danilo V. Rogayan Jr. RMTU San Marcelino

2 Outline I Categories of Proteins Fibrous proteins Globular proteins II Protein Denaturation & Renaturation III Functions of Proteins IV Journal Related to the Topic V Summary of Concepts

3 Categories of Proteins

4 Categories of Proteins Fibrous protein (found in skin, tendons, bones, and muscles) does not dissolve in water (hydrophobic). Globular protein (found in enzymes, some hormones, and hemoglobin) can dissolve in water (hydrophilic).

5 Globular and fibrous proteins Globular Protein Have complex tertiary and sometimes quaternary structures. Folded into spherical (globular) shapes. Usually soluble as hydrophobic side chains in centre of structure. Roles in metabolic reactions. E.g. enzymes, haemoglobin in blood. Fibrous Protein Little or no tertiary structure. Long parallel polypeptide chains. Cross linkages at intervals forming long fibres or sheets. Usually insoluble. Many have structural roles. E.g. keratin in hair and the outer layer of skin, collagen (a connective tissue).

6 Globular and fibrous proteins Globular Protein Have complex tertiary and sometimes quaternary structures. Folded into spherical (globular) shapes. Usually soluble as hydrophobic side chains in centre of structure. Roles in metabolic reactions. E.g. enzymes, haemoglobin in blood. Fibrous Protein Little or no tertiary structure. Long parallel polypeptide chains. Cross linkages at intervals forming long fibres or sheets. Usually insoluble. Many have structural roles. E.g. keratin in hair and the outer layer of skin, collagen (a connective tissue).

7 Fibrous Proteins Keratins are a family of fibrous structural proteins

8 Globular Proteins Enzymes are proteins that catalyze (i.e. accelerate) chemical reactions.

9 Denaturation and Renaturation of Proteins

10 What is Denaturation? Process of partial or total alteration of the native secondary, and/or tertiary, and/or quaternary structures of proteins or nucleic acids resulting in a loss of bioactivity. It leads to temporary or permanent loss of activity.

11 When and How are Proteins Denatured? At Very High or Low ph. At Very High Temperatures. By Heavy Metal Ions. By Small Polar Molecules.

12 A protein s conformation can change in response to the physical and chemical conditions. Changes in ph, salt concentration, temperature, or other factors can unravel or denature a protein. These forces disrupt the hydrogen bonds, ionic bonds, and disulfide bridges that maintain the protein s shape. Some proteins can return to their functional shape after denaturation, but others cannot, especially in the crowded environment of the cell. Usually denaturation is permanent

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14 Denaturation by Small Polar Molecules Urea ( CO(NH 2 ) 2 ) in concentrated solution will denature proteins. It disrupts the Hydrogen Bonds. This causes complete denaturation.

15 Everyday Examples of Denaturation When milk curdles, the acidity increases. Thermal denaturation by cooking. Mechanical denaturation when whisking an egg. Perming hair breaks then reforms the disulphide bonds.

16 Function of Proteins

17 Types of proteins according to functions Type catalytic transport structural defense regulatory contractile storage nutrient Examples enzymes: trypsin, nuclease, amylase hemoglobin, glucose transport protein A collagen, elastin, keratin antibodies, fibrinogen insulin, thyroid stimulating hormone actin, myosin ferritin seed proteins

18 Journal Related to the Topic

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20 Summary of the Concepts

21 Summary There are two categories of proteins: the fibrous protein and globular protein. Process of partial or total alteration of the native secondary, and/or tertiary, and/or quaternary structures of proteins or nucleic acids resulting in a loss of bioactivity. Proteins have a multitude of functions required for life.

22 Quiz Complete the table below. Type One Example transport structural defense regulatory contractile

23 References es-of-protein.html biochemistry)

24 Marami pong salamat!