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Amino Acids. Amino Acids. Amino Acids. Amino Acids. Properties of Amino Acids. Ques. 4: Use the above structures to answer the questions below: a. Which amino acid is most polar? b. Which amino acid is least polar? c. Which amino acid has an acidic side chain?
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Properties of Amino Acids • Ques. 4: Use the above structures to answer the questions below: • a. Which amino acid is most polar? • b. Which amino acid is least polar? • c. Which amino acid has an acidic side chain? • d. Which amino acid has a basic side chain?
Properties of Amino Acids • Ques. 5: Use the below structures to answer the questions: • a. Which amino acid is most polar? • b. Which amino acid is least polar? • c. Which amino acid is the most polar looking at thr and ser? • d. Which amino acid is the least polar looking at asp and glu?
Amino Acids • Zwitterion - acid and amine react with each other internally.
Amino Acids • -> -> Increasing pH -> -> • pH << pK << pH • Acids: HA molecular A- ionic • Bases: BH+ ionic B molecular
Amino Acids • -> -> Increasing pH -> -> • pH << pK << pH • Acids: HA molecular A- ionic • Bases: BH+ ionic B molecular
Amino Acids • -> -> Increasing pH -> -> • pH << pK << pH • Acids: HA molecular A- ionic • Bases: BH+ ionic B molecular
Amino Acids • -> -> Increasing pH -> -> • pH << pK << pH • Acids: HA molecular A- ionic • Bases: BH+ ionic B molecular • Mixture of val pI = 6; asp pI = 2.8, lys pI = 9.7in a buffer at pH = 6. What is the form of each?
Reactions Amino Acids - Salt Formation • Acid + amine --> salt (acid donates H+ to amine)
Reactions Amino Acids - Disulfide • 2 thiols + (O) --> disulfide + HOH
Synthesis of a peptide • Amine + acid --> amide + HOH
Synthesis of a peptide • Amine + acid --> amide + HOH
Synthesis of a peptide • Write repeating units of backbone and add side chains