amino acid This structure is common to all but one of the α amino acids exception structure size and electric charge and which influence the solubility of the amino acids in water ID: 1032626
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2. General structure of an amino acidThis structure is common to all but one of the α - amino acids. exception structure, size, and electric charge, and which influencethe solubility of the amino acids in waterProline, a cyclic amino acid, is the exception.The R group, or side chain (red), attached to the α - carbon (blue) is different in each amino acid.Amino Acids,Peptides, and Proteinsyellow2
3. 3*Mr values reflect the structures. The elements of water (Mr 18) are deleted when the amino acid is incorporated into a polypeptide.
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7. 7oxidation of two molecules of cysteineDisulfide bonds between Cys residues stabilize the structures of many proteins.
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9. 9alanine
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11. 11Effect of the chemical environment on pKa
12. Amino acids can be joined covalently through peptide bonds to form peptides and proteins. Cells generally contain thousands of different proteins, each with a different biological activity.Proteins can be very long polypeptide chains of 100 to several thousand amino acid residues some naturally occurring peptides have only a few amino acid residues. However Some proteins are composed of several noncovalent associated polypeptide chains, called subunits.peptide bonds 12Alanylglutamylglycyllysine
13. 13differences in protein solubility2) dialysis4) electrophoresisSize-exclusion chromatography3) column chromatography Ion-exchange chromatography cation exchangers anion exchangers (also called gel filtration) Affinity chromatography5) HPLC (high-performance liquid chromatography)Proteins Can Be Separated and Purified 6) Isoelectric focusing7) Two-dimensional electrophoresis
14. 14* differences in protein solubilitypH, temperature, salt concentration, and other factors. (NH4)2SO4)*dialysis
15. exploits differences in the sign and magnitude of the net electric charge of proteins at a given pH.*Column chromatography 15
16. 16* cation-exchange chromatography
17. 17* Size-exclusion chromatography
18. 18* Affinity chromatography
19. 19* Electrophoresis
20. 20Isoelectric focusingTwo-dimensional electrophoresis
21. 21Electrospray mass spectrometry of a protein
22. 22Steps in sequencing a polypeptideIdentification of the amino-terminal residue can be the first step in sequencing a polypeptide. Sanger’s method for identifying the amino-terminal residue is shown here.
23. 23The Edman degradation procedure reveals the entire sequence of a peptide.
24. How long are the polypeptide chains in proteins?24
25. 25The Structure of Proteins
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29. 29A consensus tree of life. The tree shown here is based on analyses of many different protein sequences and additional genomic features. Branches shown as dashed lines remain under investigation.
30. از توجه شما سپاسگزارم30