Question

Which one of the following structures represents the peptide chain?

• A. $- \overset{\underset{|}{H}}{N}- \underset{\overset{||}{O}}{C}- \underset{\overset{|}{H}}{N}- \underset{|}{\overset{|}{C}}- NH - \overset{\underset{||}{O}}{C}-NH -$
• B. $-\overset{\underset{|}{H}}{N} - \underset{\overset{||}{O}}{C}- \underset{|}{\overset{|}{C}}-- \underset{|}{\overset{|}{C}}- \underset{|}{\overset{|}{C}} - \overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{|}{\overset{|}{C}}- \underset{|}{\overset{|}{C}}$
• C. $-\overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{\overset{||}{O}}{C} - \overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{\overset{||}{O}}{C}- \overset{\underset{|}{H}}{N}-\underset{|}{\overset{|}{C}} - \underset{\overset{||}{O}}{C} - \overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}-$
• D. $-\underset{|}{\overset{|}{C}} - \overset{\underset{|}{H}}{N} -\underset{|}{\overset{|}{C}} -\underset{|}{\overset{|}{C}} - \overset{\underset{||}{O}}{C}- \underset{\overset{|}{H}}{N} -\underset{|}{\overset{|}{C}} -\underset{|}{\overset{|}{C}} -\overset{\underset{|}{H}}{N} - \underset{\overset{||}{O}}{C}-\underset{|}{\overset{|}{C}} -\underset{|}{\overset{|}{C}} -$

Answer 1

Answer: (C)

$-\overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{\overset{||}{O}}{C} - \overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{\overset{||}{O}}{C}- \overset{\underset{|}{H}}{N}-\underset{|}{\overset{|}{C}} - \underset{\overset{||}{O}}{C} - \overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}-$

Answer 2

The peptide linkage $(- NH - CO -)$ is formed by the condensation of amino acids molecules. $HNH - \underset{\overset{|}{R}}{C}H-\underset{\overset{||}{O}}{C} - OH$ $+ H \cdot NH - \underset{\overset{|}{R}}{C}H- \underset{\overset{||}{O}}{C} - OH \to$ $- HN - \underset{\overset{|}{R}}{C}H- \underset{\overset{||}{O}}{C}-NH - - \underset{\overset{|}{R}}{C}H- \underset{\overset{||}{O}}{C}$ Hence, following structure represent the peptide chain. $-\overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{\overset{||}{O}}{C} - \overset{\underset{|}{H}}{N} - \underset{|}{\overset{|}{C}}- \underset{\overset{||}{O}}{C}- \overset{\underset{|}{H}}{N}-\underset{|}{\overset{|}{C}} - \overset{\underset{||}{O}}{C}-$