BCH 380 Spring 2012 Name 1 Draw the amino acid with the one letter code E in its different ionized forms going from pH of 0 14 and calculate the pI given the following pKa s acid group 2 2 amino group 9 3 R group 4 2 2 Draw D serine using a Fischer projection and R Serine using a Newman Projection 3 Draw the dipeptide YF and show the position of the Phi and Psi angles 1 BCH 380 Spring 2012 Name 4a From the following graph state the type of inhibition for Panels B C and D and describe how Vmax and Km change for each 4b In Panel A no inhibitor if the equation for the line was y 2x 5 calculate Km Vmax and kcat for this enzyme with a concentration of 1 x 10 6 M 5 Which of the following are considered as noncovalent bonds A electrostatic interactions B hydrogen bonds C van der Waals interactions 2 BCH 380 Spring 2012 Name D All of the above E None of the above 6 Which of the following amino acid residues would most likely be buried in the interior of a water soluble globular protein A Asp D Lys B Ser E Gln C Phe 7 Why is the peptide bond planar A Bulky side chains prevent free rotation around the bond B It contains partial double bond character preventing rotation C Hydrogen bonding between the NH and C O groups limits movement D None of the above E All of the above 8 The sheet structure occurs when the two strands are oriented in opposite directions N C 9 Which secondary structure is stabilized by CO and NH hydrogen bonding within the peptide chain 3 BCH 380 Spring 2012 Name 10 The difference between the standard state free energy G and the biochemical standardstate free energy is that G refers to the standard free energy change at 11 Allosteric enzymes can be identified because the plot of initial velocity V0 versus substrate concentration S is not hyperbolic but shaped 12 A inhibitor has a structure similar to the substrate and reversibly binds to the active site of the enzyme 13 Allosteric proteins A contain distinct regulatory sites and have multiple functional sites B display cooperativity C always consist of several identical subunits D a and b E a b and c 14 The model describing allosteric regulation that requires all subunits to be in the same state is called the A concerted model B syncopated model C cooperative model D equilibrium model 4 BCH 380 Spring 2012 E Name None of the above 15 Allosteric modifiers alter the equilibria between A the ES state B the R and T forms of a protein C the forward and reverse reaction rate D the formation of product and it s reverse reaction E All of the above 16 From the above drawing state what type of inhibition each is showing and draw the appropriate E S I reaction equilibrium 5 BCH 380 Spring 2012 Name 17a What is the pH of a 0 3 M solution of an acid given the Ka is 1 75 x 10 5 17b What is the resulting pH after addition of 0 5 mole equivalents of base i e 0 15 M NaOH Appendix Formulae 1 Vo Km Vmax x 1 S 1 Vmax 6 BCH 380 Spring 2012 Name Vmax k2 E 7