CHEM 4511 PS 4 F10 Solutions

CHEM 4511 PS 4 F10 Solutions - CHEM 4511 PS 3 Fall 10 1....

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Unformatted text preview: CHEM 4511 PS 3 Fall 10 1. Average molecular weight in amino acid = 110 Da 2. EHWSGLRPG 682 × 10 = 75,020 Da pK a 4.1 CO2H HN NH2+ pK 12 a NH Ionizeable groups on side chains, for indicated pH's,indicated H3N-Glu-His-Trp-Ser-Gly-Leu-Arg-Pro-Gly-CO2H p Ka -9.6 pK 3.5-4 a HN p Ka 6 NH A. pH 3 NH2+ CO2H HN NH Net charge: +3 H3N-Glu-His-Trp-Ser-Gly-Leu-Arg-Pro-Gly-CO2H HN NH pH 8 NH2+ CO2 - HN NH Net charge: 0 H 3N-Glu-His-Trp-Ser-Gly-Leu-Arg-Pro-Gly-CO2N NH pH 11 NH2+ CO2HN NH Net charge: -1 H2N-Glu-His-Trp-Ser-Gly-Leu-Arg-Pro-Gly-CO2N NH 3. (A) (E)20 4. not present on questions 5. (B) Ser–Val–Trp–Asp–Phe–Gly–Tyr–Trp–Ala 6. A = ε • c • l 7. (A) Asp 8. Leu, then His, then Arg 9. (A) 32,069 Da 10. Lysines (and Arg + His) ⊕ of side chain can form electrostatic interactions with the phosphate groups of DNA. Molecular weight Trp: 204 Da; when in a protein have to subtract MW of H2O = 186 Da (B) Met (C) Gly A = (0.3 mL • mg‐1 • cm‐1) (2.3 mg • mL‐1) (1) A = 0.69 (B) (KA)3 (C) (NSH)5 (D) (Asn–Ser–His)5 (B) 2 11. (A) Step 1 2 3 4 5 6 12. (A) 0.5 mM NaCl (1000× dilution) 13. In order: C, then B, then A 14. YGGFL 15. Tetramer: α2β2 α subunit: 40 kDa β subunit: 60 kDa Subunits linked together by a disulfide bond (a covalent bond) and noncovalent interactions form the intact tetramer A. Accounts for the molar ratio B. Y at N terminus; only at N terminus (as suggested by complete H+ hydrolysis of remaining peptide) C. Chymotrypsin cuts after Y, F; only way to piece together this peptide (B) 0.05 mM NaCl (100× dilution × 100× dilution) (B) Step 4 = Ion exchange: a 16× increase in specific activity. (C) Step 3: pH precipitation (D) Yes: Specific activity did not improve further. SDS – PAGE to show a single band would confirm this assumption. Specific Activity µ ( ) 200 600 250 4,000 15,000 15,000 16. A. 2 B. 5 C. 2 D. 3 possible combinations ...
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This note was uploaded on 11/04/2010 for the course CHEM 6501 taught by Professor Wendyl.kelly during the Fall '10 term at Georgia Tech.

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