Quick Exercise 1: Amino Acids and Isoelectric Points

1. This is an individual activity.
2. Please answer the questions below on a sheet of paper or what have you. Use the attached pka table to help you with your answers.
3. Submit your answers in pdf/jpg formats only.
4. Follow the file naming format: Chem40_QE1_<Section>_<LastName,Initial of First Name>. Example: Chem40_QE1_MHD_LimC

Problems

1. The pKa of the side chain of Histidine is 6.0. What is the ratio of uncharged to charged side chains at pH 7.0?
2. What is the pI of E?
3. In general, is the pI of an amino acid equal to the physiological pH? Is this a good thing or a bad thing? Why?
4. Draw L-aspartyl-L-phenylalanine? Calculate its pI.