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Chemistry and Biochemistry Part 4. For Advanced Diploma students of the WEA Hunter Academy of Complementary Health. Chapter 6. NON-CATALYTIC PROTEINS: providers of structure and functionality. Two main groups. Fibrous And Globular. Globular proteins.
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Chemistry and BiochemistryPart 4 For Advanced Diploma students of the WEA Hunter Academy of Complementary Health (c) WEA Hunter Academy of Complementary Health. Created by John Radvan. Reproduction or transmission without the express permission of the author is prohibited.
Chapter 6 NON-CATALYTIC PROTEINS: providers of structure and functionality
Two main groups Fibrous And Globular
Globular proteins • Although long, they have short secondary structure sections (remember those?) • Lots of hydrophobic interactions in the core • Myoglobin and Haemoglobin • Contain ‘haem’ as the prosthetic group • Are related, but occur in different parts of the body
Myoglobin and Haemoglobin • Read all about Myoglobin and Haemoglobin on p62-64 and complete the following activities as you go: • Haem (can you draw a simplified structure? How does it connect to the protein?) • Myoglobin • Name two amino acids that occur in Myoglobin, where are they located? • What is ‘oxygenation’?
Myoglobin and Haemoglobin • Haemoglobin • What is HbA? What does it look like? • What interaction causes α-globin to connect to β-globin? • How do the dimers bond together? • What is the difference between the T form and the R form? • What is ‘cooperative binding’? • How is HbF different to HbA?
Immunoglobulins • Are also known as ‘antibodies’ • Manufactured by ‘B’ cells (immune cells) • Foreign bodies are ‘antigens’ – usually polypeptides, can be polysaccharides, lipids, nucleic acids. • Antibodies bond to a region on the antigen called the ‘epitope’ • Let’s study the Ig’s in Table 6.1
Immunoglobulins • Read only the first paragraph on page 65 and define the following: • Hypervariable region • Heavy Chain and Light Chain
Fibrous Proteins • Mainly ‘structural’ proteins, but their structure determines their function • Collagen: • What does collagen look like? • How do the polypeptides hold together? • Define homopolymer and heteropolymer • What is ‘hydroxylation’? What is ‘glycosylation’? (see Fig 6.8) • Why does collagen need to be ‘strong’? Where is it located? What visible affect would collagen wear have on the body?
Membrane Proteins • SYMPOSIUM!!!!!!!!!!!!!!!!!! • Break into 3 groups: each group will study a membrane protein (integral, perpheral and lipid anchored) • You know the drill, study and report back…
Private study • Read and summarise ‘When things get sticky!’ on p71
Chapter 7 • ENZYMES: catalytic proteins
Enzymes • ‘Catalysts’ – speeder-upperers • Read the section ‘Naming enzymes’ – you will encounter this terminology a lot in your career! • Let’s all go through Table 7.1 – it’s very important to learn!
Enzyme properties • Active site – portion of the protein where the ‘substrate’ fits – grabs, speeds up, lets go • Specific – usually specific to one, or closely related substrate • Possible Cofactor Relationship – may require ‘something else’ to make it all work • Efficient – high turnover, hundreds to thousands of products per second • Controllable – can be switched on and off • Location-controlled – only present where they are needed, possibly within organelles
Activation Energy • Read ‘What slows spontaneous reactions’ to learn about Activation Energy • The ‘energy hill’ analogy is particularly useful to understand it. • Enzymes work by lowering the activation energy. • What is ‘transition-state stabilisation’? • What is ‘general acid-base catalysis’?
Enzyme Inhibition • Competitive – inhibitor competes with the substrate for the active sites due to being chemically similar. Can be overcome by adding more substrate (causes displacement) • Non-competitive – inhibitor binds elsewhere on the enzyme, this stops the substrate from entering the active site. More effective, adding more substrate has no effect • Many drugs are inhibitors (both allopathic and natural!) – see table 7.2
Enzyme Control • Write definitions for the three main ways enzyme activity is controlled: allosterism, covalent modification, rate control. • Study the figures on p82-83 to help your understanding.
A BIG SYMPOSIUM • We are going to try a ‘contextual’ symposium tonight • Split into 3 groups and each study a ‘Clinical Example’ from the textbook related to enzymes. This will take time. Put together a short presentation assuming only very basic knowledge of your audience.