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Proteins: Their Biochemistry and Functions.

Proteins: Their Biochemistry and Functions. By: Quy Le (#6) URL:   http://proteins1.tripod.com Organic Chem. 12 B Spring-2005. Outline. I) History of proteins : - Jöns Jacob Berzelius and Gerharus Johannes Mulder coined the term “protein”.

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Proteins: Their Biochemistry and Functions.

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  1. Proteins: Their Biochemistry and Functions. By: Quy Le (#6) URL:  http://proteins1.tripod.com Organic Chem. 12 B Spring-2005

  2. Outline I) History of proteins: - Jöns Jacob Berzelius and Gerharus Johannes Mulder coined the term “protein”. - Investigation of proteins and their properties began 1800. II) Protein’s structure: - Many amino acid units link together to make up proteins. - Primary structure: the linear arrangement of amino acids. - Secondary structure: areas of folding or coiling. - Tertiary structure: the final three-dimensional structure. - Quaternary structure: non-covalent interactions.

  3. III) Functions of Proteins: - Enzymes (catalytic activity & function)* - Transport Proteins ( bind &carry ligands)* - Storage Proteins ( ovalbumin, gluten, ferreting) - Movement (muscles; can contract) - Mechanical support (collagen-bone, keratin)* - Defensive-protect ( antibodies, bacterial toxins) - Regulatory-signal ( metabolic, hormones) - Receptors-detect stimuli ( membrane receptor, and acetylcholine or insulin)*

  4. IV) Disease Related with Proteins: - Sickle cell disease - Marfan Syndrome - Diabetes

  5. I. History of Proteins. - It started from late 1700’s, Physiological chemists was trying to understand the materials that made up living cells. They identified albuminoids from coagulation of egg… - In 1800’s, Chemists set out to identify the chemical makeup of proteins (exp. Water= H2O; Methane= CH4) - By 1838, a Dutch chemist, Gerardus Mulder presented is finding that albuminoids had high quantities of nitrogen and small amounts of sulfur. http://www.madsci.org/posts/archives/feb98/888588800.Sh.r.html

  6. July 10, 1838, a Swedish biochemist Jöns Jacob Berzelius suggested Mulder to give the albuminoids more special name because it appear to be a principal substance of animal nutritionthe word Protein (meaning of primary importance) was used. - In 1930s, the famous work of Moses Kunitz and John Hward Northrop at the Institute in New York City convinced the world; they studied three different chemical reactions came from three different proteins.-In 1953, Sanger’s experiments showed that proteins have a unique amino acid sequence. He also showed for the first time that all amino acids in mammalian proteins are in the S-configuration, peptide bond is an amide bond, and amino acids have alpha amino groups and alpha carboxyl groups.http://wiz2.pharm.wayne.edu/biochem/prot.html

  7. II. Protein’s Structure: - Proteins are very complicated molecules. With 20 different amino acids that can be arranged in any order to made a polypeptide of up to thousands of amino acids long. http:// www.chembio.uoguelph.ca/educmat/phy456/gif/peptide5.gif

  8. - Basic structure: - All amino acids found in proteins have this basic structure, differing only in the structure of the R-group 1. A alpha hydrogen: H 2. A alpha amino group: -NH2 (basic) 3. A alpha carboxyl group: -COOH (acidic) 4. A side chain: R (20 possible) A. Structure of Amino Acids in Proteins: http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html

  9. - All of the amino acids used in proteins (except for glycine which is not optically active) are of L-configuration. - However in R/S notation Cysteine is 2R, whereas the others are 2S. B. Stereo Configuration of Amino Acids. http://bmbiris.bmb.uga.edu/wampler/tutorial/aaconfig.html

  10. - The 20 different R groups give amino acids individual characteristic. They are grouped in four major groups according to their characteristics. C. Classifying of Amino Acids http://www.ucl.ac.uk/~sjjgsca/ProteinStructure.html

  11. - Polypeptides and proteins are formed of chains of amino acids joined together by linkages called peptide bonds. - Peptide bond formation is an example of a condensation reaction , whereas a molecule of water is released. http://saints.css.edu/bio/schroeder/proteins.html - Peptide Bond Formation: D. Bonding in Amino Acids

  12. - The primary structure of a protein is its linear sequence of amino acids and the disulfide (-S-S-) bridge; all covalent connection in a protein. - The amino terminal or “N-terminal”(NH3+) at one end; carboxyl terminal “C-terminal” (COO-) at the other end. http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Polypeptides.html E. Primary Structure of Proteins

  13. - Alpha-helix: described by Linus Pauling; has a rod shape. The peptide is coiled around like a cylinder and stabilized by H-bonds formed between peptides - Beta-pleated sheets: adopt the conformation of a sheet of paper and the structure is stabilized by H-bonds between amino in different polypeptide strands. http://www.rothamsted.bbsrc.ac.uk/notebook/courses/guide/prot.htm#II http://www.ekcsk12.org/science/apbio/biochemnts.html F. Secondary Structure of Proteins

  14. - Tertiary structure is the way the secondary structure fold onto themselves to form a protein or a subunit of a more complex protein - Amino acids which are very distant in the primary structure might be close in the tertiary one because of the folding of the chain. http://www.rothamsted.bbsrc.ac.uk/notebook/courses/guide/prot.htm#II http://www.ekcsk12.org/science/apbio/biochemnts.html G. Tertiary Structure of Proteins

  15. - Complexes of 2 or more polypeptide chains held together by noncovalent forces but in precise ratios and with a precise 3-D configuration. - A good example is the quaternary structure of hemoglobin, made up of 2 alpha and 2 beta polypeptide chains. H. Quaternary structure of Proteins http://www.ekcsk12.org/science/apbio/biochemnts.html http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/Q/QuaternaryStructure.html

  16. III. Function of ProteinsA. Proteins as catalyst - Proteins that act like catalysts in chemical reactions are called enzymes. - Enzymes are the catalysts which make possible biochemical reactions. Catalyst increase the rate of a reaction, but are not themselves consumed or produced by the reaction. - Enzymes are grouped into six classes according to the kind of reaction they catalyze

  17. http://courses.cm.utexas.edu/jrobertus/ch339k/overheads-2/ch8_enzyme-classes.jpghttp://courses.cm.utexas.edu/jrobertus/ch339k/overheads-2/ch8_enzyme-classes.jpg

  18. - Proteins in the Plasma Membrane include: 1. Transport channel (D), which ions and macromolecules may pass 2. Enzymes(I): provide a convenient surface for enzymes to be embedded. 3. Cell surface receptors (B): fit only to specific substances. 4. Cell surface identity markers (E): each cell carries its own ID markers 5. Cell adhesion proteins (A): adjacent cells stick together via interlocking proteins on their membranes. http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/cells/notes/ch6/ch6menu.htm B. Receptors

  19. - Hemoglobin is a protein that is carried by red cells. It picks up oxygen in the lung and delivers it to the tissues to maintain the viability of cell. - Hemoglobin is made from two similar proteins that stick together. http://www.chem.purdue.edu/chm333/hemoglobin.JPG C. Transport Protein - Hemoglobin http://www.medical-definitions.net/hemoglobin.htm

  20. D. Mechanical support - About one quarter of all of the protein in our body is collagen. - Collagen provides structure to our bodies, protecting and supporting the softer tissues and connecting them with the skeleton. - Collagen is composed of 3 chains, wound together in a tight triple helix. Every third amino acid is a glicine, and many of the remaining amino acids are proline or hydroxyproline. http://www.rcsb.org/pdb/molecules/pdb4_1.html

  21. - Sickle cell disease a genetically disorder affecting 1out of 10 African Americans. - Disease is cause by mutation in the gene responsible for the production of hemoglobin. Substitution of a single amino acid ( valine for glutamic acid) in the sixth position of the B-chain of the hemoglobin molecule produces a hydrophobic. - The defective hemoglobin forming long rods that stretch a red blood cell into a crescent too large to fir through small blood vessels. http://encarta.msn.com/media_681500788/Sickle-Cell_Anemia.html http://www.coe.neu.edu/research/berl/BERL_research_sicklecell.html IV. Disease Related with ProteinsA. Sickle Cell Disease

  22. B. Marfan Syndrome - Marfan syndrome is a heritable (in 75%) disorder of connective tissue that affects many organ systems including the skeleton, lung, eyes, heart and blood vessels. Affect both men and women, of any race and ethnic group. They are typically very tall, slender, and loose jointed - In Marfan syndrome a protein called fibrillin is deficient or abnormal. Fibrillin is part of elastic fibres, accounting for the unusual stretchiness and weakness of tissues. - A mutation in the fibrillin gene on chromosome 15 is said to be responsible for the production of abnormal fibrillin molecules which can’t function properly. http://www.nlm.nih.gov/medlineplus/ency/imagepages/9611.htm http://www.marfan.net.au/showcontent.toy?cid=1515

  23. C. Diabetes - Diabetes occurs when the body can't produce enough insulin, or when the insulin that the body makes does not work properly. - Type 1 Diabetes: because the insulin-producing cells of the pancreas are destroyed by the immune system. People with type 1 diabetes produce no insulin and must insulin injection to control their blood glucose. http://my.webmd.com/content/article/46/1667_50911?src=pemedscape

  24. Type 2 Diabetes - People with type 2 diabetes produce insulin. However, the insulin their pancreas secretes is either not enough or the body is unable to recognize and use it properly. - When there isn’t enough insulin or the insulin is not used as it should be, glucose can’t get into the body’s cell. - It affects 18 mill. Americans; usually occurs in people over age 40 who are overweight. http://my.webmd.com/content/article/46/1667_50911?src=pemedscape

  25. Conclusion - Proteins are one of the classes of bio-macromolecules, that make up the primary constituents of living things. - They are essential to the structure and funstion of all living cells and viruses. - They are amongst the most actively studied molecule in biochemistry .

  26. V. References • http://www.madsci.org/posts/archives/feb98/888588800.Sh.r.html • http://wiz2.pharm.wayne.edu/biochem/prot.html • http://www.chembio.uoguelph.ca/educmat/phy456/gif/peptide5.gif • http://www.biology.arizona.edu/biochemistry/problem_sets/aa/aa.html • http://bmbiris.bmb.uga.edu/wampler/tutorial/aaconfig.html • http://www.ucl.ac.uk/~sjjgsca/ProteinStructure.html • http://saints.css.edu/bio/schroeder/proteins.html • http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Polypeptides.html • http://www.ekcsk12.org/science/apbio/biochemnts.html - http://courses.cm.utexas.edu/jrobertus/ch339k/overheads-2/ch8_enzyme-classes.jpg - http://ghs.gresham.k12.or.us/science/ps/sci/ibbio/cells/notes/ch6/ch6menu.htm • http://www.chem.purdue.edu/chm333/hemoglobin.JPG • http://www.rcsb.org/pdb/molecules/pdb4_1.html • http://www.coe.neu.edu/research/berl/BERL_research_sicklecell.html • http://my.webmd.com/content/article/46/1667_50911?src=pemedscape

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