Answers to representative text questions

Chapter 3 Voet and Voet

3.  There is a limited number of positions a car can be in when pulling into a small parking space, however when pulling out more positions are available.  Thus, greater entropy is associated with pulling the car out.

8.  a.  *G = 6(-382.2) + 6(-237.2) - (-917.2) - 6(0) = -2823.2 kJ/mol

     b. *G = 2(-181.5) + 2(-386.2) - (917.2) = -218.2 kJ/mol

     c. *G = 2(516.6) + 2(0) - (917.2) = -116.0 kJ/mol

Chapter 4 Voet and Voet

2.  a.  If drawn correctly the tripeptide should have a +1 charge.

     b.  If drawn correctly the tripeptide should be neutral.

     c. If drawn correctly the tripeptide should be neutral.

3.  5 x 4 x 3 x 2 x 1 = 120

Chapter 5 Voet and Voet

3.  P-cellulose binds cations so order of elution is aspartate, leucine, histidine and arginine.

4.  CM-cellulose is a cation exchange matrix.  The higher the pI of the protein the more cationic.  Thus, order of elution is pepsin, fibrinogen, hemoglobin, ribomuclease, and lysozyme.

6.  Sephadex fractionates molecules in the range of 1 to 30 kD.  Thus, order of elution is  catalase, concavalin B, chymotrysin, myoglobin and lipase.

9.  a.  choose a method based on polarity such as paper or thin layer chromatography.

     b.  choose a method based on charge such as CM-cellulose...also consider pH.

     c.  choose a method based on size such as gel filtration and then choose appropriate matrix such as Sephadex G-100.

Chapter 6 Voet and Voet

1.  a.  cuts between Phe and Lys

     b.  cuts between Met and Asn

     c.  cuts between Arg and Gly and between Gly and Asp

     d.  cuts between Gly and Phe and Phe and Trp

     e.  cuts between Arg and Glu

2.  Possibly three polypeptides;  one with Ala end and two with Ser end.

5.  Trp-Ala-Lys-Asp-Phe-Trp-Ser-Ser-Ala-Pro-Cys-Leu

6.  Tyr-Arg-Gly-Met-Asp-Ile-Lys-Gln-Met-Lys-Phe-Ala-Met-Lys