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Final_exam_key_part_ - hwwan lg Name CHM 3218 CHM 5305 Summer 201 1 Final Examination — Part 1 University of Florida Honor Code Statement"On

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Unformatted text preview: hwwan lg Name CHM 3218/ CHM 5305 Summer 201 1 Final Examination — Part 1 University of Florida Honor Code Statement: "On my honor, I have neither given nor received unauthorized aid in doing this assignment. ” Student signature Instructions: You have 75 minutes to complete this section of the exam. All books, smart phones, translators, notes and other aids are prohibited, but calculators and molecular models are allowed (no sharing of calculators or molecular models, however). Be sure to budget your time and answer questions briefly but completely. To receive partial credit for incorrect answers, be sure to show your work, particularly in problems involving calculations. Write your name on each page. 1. Arginine biosynthesis and properties. (Total 48 points). a. Arginine biosynthesis involves a total of nine enzyme-catalyzed steps, and a-ketoglutarate serves as the starting point. The overall result of the first six steps is that a-ketoglutarate is converted to ornithine and this pathway involves five intermediates whose structures are shown below (labeled 1 — 5). Based on your knowledge of biochemistry, place the intermediates in their most likely order (you only need to write the structure numbers, not the structures themselves). (3 points each). i O 002— H3N C02 j 6 steps ——> —> — + C02 NH3 a-ketoglutarate ornithine _ H _ CH3 co2 H , H CHgTN 002 CH3\n/N (:02 \n/N o O J o co; 0 O (I? ,3/ o H —P—o | a o_ H _ + _ CH3\n/N co2 H3N co2 o (T [I “HS CO; 4 _.._37 2L ——~»L\ ——»» @vn'ktuvu, Ol—\u.\—oc&u‘rw0\4- -—-—» 5 M» Z ~‘> 3 BM 3‘93 EA: Name b. The conversion of ornithine to arginine involves three enzyme—catalyzed steps (shown below). Where a box appears below an arrow, indicate the cofactor most likely to participate in the reaction. If no cofactor is required, write “None” in the box. A list of all the cofactors discussed in lectures appears near the end offhe exam. (3 points each). + + _ - ATP, AMP, H3N co2 o 0 Pi H3N 002 Asp PP] + HZN/LLOvfi‘,_O— A éé + 0— NH3 NH carbamoyl ornithine phosphate 0%NH2 MOM citrulline + _ H3N 002 00; it —~ r + _ HN NH2 O20 Hafi)\ NON» fumarate 002 arginosuccinate c. Use curved arrows to show a mechanism for the enzyme-catalyzed conversion of citrulline + ATP + Asp to arginosuccinate + AMP + PR. Be sure to use the cofactor (if any) indicated in your answer to part b. You may use acid-base catalysis as needed and stereochemistry can be neglected in your structures. (8 points). AN‘quE‘l \Ce‘t Name (1. Use curved arrows to show a mechanism for the enzyme-catalyzed conversion of arginosuccinate to L—Arg + fumarate. Be sure to use the cofactor (if any) indicated in your answer to part b. You may use acid-base catalysis as needed and stereochemistry can be neglected in your structures. (8 points). 6) e _ 6 e . A e . _,_> co ) ’71") 6 HQ” )/\ N co? V” Hz“ a\N co? va— HZ») /\ '3‘ VCOZ :2: Z H O /O~\a\ (. x ” J." \l \ ’ O.- 47“. V, r , Q.., FEW“ V06) 3-13' V \40 l?) ‘J‘ L Ll H’B'H 3_\g1 V p + - (5 ~ €> ‘ G) /\ 7' ———~a- NH / Him / NHz W] n ‘ \Ii 0 \«Owa Hg AW: 0 H5: 0 ’\~—/ )fing) 93‘“ +544 6. What is the numerical value for the isoelectric point of arginine? (3 points). 6 to ‘4 G5 7 (’3 H NVCOQ ) e MEN 2 Zn 8 HSN v z qoq 7. a ‘2)“ Man VLQL ::;_.) \«\ —¥ 6 ;: He \- \_..3 HQ ‘_ 6 3H4 NH :3} NH 6 /\N\.\ (1) /\ K a. Z 7'. 1 O (CLO‘H + LVLH‘U I (W "P L ‘ Z = \OC‘IL, no; \g cm \C&‘\ Name f. What is the concentration of the form of L-Arg with a net charge of +1 at pH 8.5 if the total concentration of L-Arg is 50 mM? (4 points). . , , ‘ xix—1 ( \k— ‘0‘) ml V ‘3!“ ‘ MCA land) WAX * [MAX-‘0 ? v " EMA" llmlV : (“3* \Nl KW“ L\ * \OC?“'?W~\) : [Hka i «on 2'2“; “€33 taunt - HQ “WM 47 MA A” HQ ' [HM : ‘k mew-PKG) (*1) (50 mg) [AC1 ; XHKXT -l_\—\b\\ : ¥ ‘OKL%.S‘) —tq.ox\)) HAM V NAM) PH : PKQ m5 M1 = 33-59 Mi V (mum - LAM) w a it t M CNN“) ( [WOT NM) '0 1 [Hbfl L Q. \Cc.) . \xm \o P V - {HAL—mm g. What would be the final pH value if 1.3 mL of 2.0 M NaOH were added to 300 mL of the L— Arg solution described in part f (starting pH = 8.5)? (4 points). MGM). o‘» HA 0* ?\‘\ fi‘fi‘ W‘Ob‘b 0Q \FL'YA‘XT: “ , . I ‘ . \L _ w x " ’- 0.0l5 L. \OOOMmcl 7. \ ' Q 6‘ We“ “ "300 "‘Wl \ moms 09‘ Gem CAME ‘. \3) w-‘L L’ 1~ Z'0 "‘3‘ - r \ * OrOOZ. m0 \ 7‘ “>60 ML— 1.— g Mac» 3 ms at» Meow (e_o\\b men->1 v Loeozg mew») ‘ 000610 New "101.» o\ ’5: NCmOH . O. Q - \b (O.©\S Make-'3) - (0,60q0mOUJJ) 00 D MD wheat \OBC—Eik = mom» Web (tooofiowowllon-D ' ‘ Name Alanine Arginine Asparagine Aspartate Cysteine Glutamate Glutamine Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Proline Serine Threonine Tryptophan Tyrosine Valine pKa 1 2.34 2.17 2.02 1.88 1.96 2.19 2.17 2.34 1.82 2.36 2.36 2.18 2.28 1.83 1.99 2.21 2.11 2.38 2.20 2.32 Amino acid pKa values Useful physical constants 3.65 8.18 4.25 6.00 10.53 10.07 R (Universal gas constant) = 1.987 cal/mole-K F (Faraday’s constant) = 23.1 kcal/rnole-V Answerc \de‘i Name Amman K91 Name Names and Structures of Some Important Enzyme Cofactors NH2 NH2 H/' H O JOL / N NH 6) 9H3 (NIKN \> 9 H W 2 HN NH WNW/V?) o N “A \N HOE—ago o N We” 002' K? (3,95 9 e S i . OH OH OH OH Biotin S-adenosylmethionine (SAM) R = H, Nicotinamide adenine dinucleoiide (NADH) R 2 P05, Nicotinamide adenine dinucleotide phosphate (NADPH) o 0 CH3 N \NAO CH3 N \N’go H——H H——H H——OH H——OH H—OH H——OH H—J—OH H~——OH _9 9 '9 9 O=i|3-O O:F|’—O—P—O 09 06 Fiavin mononucleotide (FMN) NH2 0 OCH3CH3 9 9| </N |\N HSWNMNMO—g—O—g—O O N N; H H OH 9 G) =ospo OH Coenzyme A (00A) 9 O H CH30 CH3 0 / I o—i‘f—oe 0 CH3 \N® @ CHso \ H H 0 CH3 n Pyridoxal phosphate n = 6.10 Ubiquinone (Q) NH2 CH3 0 0 ® _II_ _II_ 6 N/ I NI/gfo (i; o I o OHS/KN L5 9 e Thiamine pyrophosphate (TPP) I N N 06 T:0:1 OH OH Flavin adenine dinucieotide (FAD) O 002' OANMCOé O “ HN FIN/Li )2 J\\ HZN N N H Tetrahydrofoiate (TH F) COg' S / S Lipoamide ...
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This note was uploaded on 09/18/2011 for the course CHM 3218 taught by Professor Stewart during the Spring '08 term at University of Florida.

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Final_exam_key_part_ - hwwan lg Name CHM 3218 CHM 5305 Summer 201 1 Final Examination — Part 1 University of Florida Honor Code Statement"On

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