4033exIbluekeysum11

4033exIbluekeysum11 - BCH 4033 Summer 2011 [/2 Name; f r...

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Unformatted text preview: BCH 4033 Summer 2011 [/2 Name; f r 55.1% Examl N-number: ’1 wiwvai “t 1,. Draw Leu and Pro in their unionized states. React the amino acids and draw the dipeptide Leu-Pro. Use curved arrows to demonstrate electron pair movement that leads to the product. Label the oxidant (ox) and the reductant (red) in the following reactions: _ W) DCIPHZ + Dehydroascorbate .C‘l gr 1, Complete the following purification table for a new enzyme found in the kidney. The tissue is homogenized in a blender with buffer and a crude extract results. Show a sample calculation for specific activity, % yield and fold purification (purification factor) with the result of the calculation. Step Protein (mg) Activity (units) Specific Activity % Yield i» m. Crude Extract 13,500 345,000 “at, g Precipitation 1,000 * 7n» Li . a 65 gt 1 3 it N f 14 Sand. MW}? j What kinds of forces would occur between R—groups at pH 8.5 in the following dipeptides (other than “‘iwrfiw’ London dispersion forces). Indicate the overall charge on the dipeptide. Force type Charge g9 w i. ser—cys {3% w ’ g: ii. trp—met 9 K: M f * \3 iii. lys—his a. i it Given a mixture of two proteins, A is myoglobin and B is hemoglobin at pH 7.0. What would be an easy way to purify them at pH 7.0? Explain and be specific. BCH 4033, Exam I, Summer 2011 ,_ An unknown 20 amino acid peptide was isolated at pH 7.0 and when administered it has the ability to “*tallow one to read people’s minds. Answer the following questions based on experiments aimed at QgtiiZ/eluciclating the peptide’s structure. Be specific and include amino acid names where possible. R1*Rz-RerA'Rs-Rt-RrRs-Rer-Rl1-R12-R13-R14-R15-R16-R17-R18-R19-R20 a. Cystine is found in the peptide. What is cystine? (complete structure not needed.) i g: w g a? 7’s j b. Chymotrypsin treatment has no effect‘on the peptide. What can you conclude? 5 W6? f 5;“ ff ‘9 W ’jg'w m gag WA”? 95%? V” E" c. Dansyl chloride followg‘d hBzyf‘acid hydrolysis labelsaxbasic amino acid. What can you,conclude? f g g“; e t W; my ’" 4:; 3 M ‘41 if 5‘15“: *5 sir (1. Four equivalents of B-mercaptoethanol are needed to react with the peptide. What can you conclude? / fiery. (a ' . e. Draw the structure of [3-111 rcaptogifanglgnd state its purpose? w, if [3,} N, I; {aft :9 M ,j m5”; / f. At least 2 [3 turns exist in the peptide. What aminoacid is most likely to be found in these [3 turns? 4 C 7) (7 Q3?) We»: 2 M g. Carboxypeptidase releases an acidic amino acid. What can you conclude? ; Q I» y g ‘ux {K .3 t. t \; r’ L » 5:? . » f r g m a)? A; 1’3 v u at h. A reagent is added to the peptide and after acid hydrolysis a yellow amino acid is detected. What is a} the complete chemical name of the reagent? Draw the reagent. fixative... r M / unsung. /’ i. What could the yellow amino acid found in thepart (h) be? Use the information in parts (a)-(i). Si: 6965/ guy “’3’? j. Draw the electron dot structure for CNBr and name it. Based on your knowledge of organic chemistry, show the first step of the reaction between the particular amino acid in a peptide that would react with this reagent. (Use curved curved arrows to show the electron pair movement.) ‘.f"”"”'\ V; ';.;m_..‘u”y.f?;::,. _~M,M mum...“ .1. g. Q i W Mir fl: 2‘! J l A g ' aw mm M . .-,N\ ‘1 ER", 33 it A peptide is digested with trypsin yielding 4 fragments: V Glu-Phe—Lys ; Val—Glu-Ile-Phe-Arg ; Ala—Met—Ser-Arg ; Trp-Asp-Tyr-Ala-Pro-Glu 7 f "/3 f“ (“if The same peptide is digested with S. aureus V8 protease yielding fragments: Ile-Phe-Arg-Trp—Asp ; Tyr—Ala-Pro—Glu ; Phe—Lys—Val—Glu ; Ala-MthSer-Arg-Glu ? t a 2m, BCH 4033, Exam I, SummerQOll ’8 The following questions concern proteins with organized structure. Myglobin contains a large amount of what 20 structure? (71* “Ml l (7" 6%” gW‘QAC W A a; Mfif’j What force stabilizes the 29 structure in hemoglobin? H“ MW <5 0. The protein that silk is composed ofis? r“! l»; «w to K . . . . . . ts. @ f , j d. What IS the highest level of organized protein structure 1n hemoglobin? [g f ft, QWVWQ" WW ‘ ’ g? g. What is the stabilizing force in hemoglobin that produces cooperativity towards 02 J' t. 5 j t / (Q1; 7;” 5m. ( a w sit/5;? [rt car/9M»: swim binding? 1 h. What are the repeated sequences in collagen? \ t i t A A ‘ t C fifig'} é W29 92; l S. a.) 1 ~~~~~~ Draw an oxygen saturation curve below for normal adult hemoglobin (Hb) and adult hemoglobiii that has lost diphosphoglycerate (Hb~noDPG). Label the curves and label the axes in the blocks provided. ' x, v "“\W7fl If 02 is bound by Hb and there is 3.5 mM free Hb and 6.0 mM oxygs fractional saturation? ShOW gxour WOku vrw’ . Hemoglobin returns to the lunwgfilrom normal tissue carrying a molecule. What is the molecule and how is it carried? Be specific and use structures and names to demonstrate how the moleculefiisrbound to ' f ‘ .s v 5 ‘t hemoglobln. {W / s v ,9 , r: 9,433; ""te “it? ,fl, de M x 3 On BCH 4033, Exam 1, Summer 2011 W ” 10. Use the axes provided to sketch the titration curve for the tripeptide gln—cys-lys for the w/flpIQI range 1—14. Label the axes in the boxes provided. List the pks for the peptide. @3291 1. Draw the structures of A‘ and HA at H 7.65 for the di e tide his- I. Label our answers. .24 ‘ _, P P P y k“ M e U M far“ {it El W e“? M Q; Ma a”, f ‘" £3 N fig, 4»? 3% 3 g; l ‘i a“ 1 ,1 W E <53: 1 “3% Eli“ '4? lift; V H2]; ‘1 g l \ mt“? k‘% l ‘ . What is the [11+] ofHCl at pH 12.38? Show all work. m J. r ‘ «ewes f m ‘ <2” We . What IS the p1 for the peptide arg-gly—asp-ser? List all the sz for the peptide. 3', 1.9% a??? my: rd?” fi‘l Show all work. M”, E e r 4) l \ .M W E“ fil‘éw gm fl 5" ,. 5 WE s.» l t i %>” z: W r] a 5;:- f t”; ...
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4033exIbluekeysum11 - BCH 4033 Summer 2011 [/2 Name; f r...

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