The peptide that gives positive ceric ammonium nitrate and carbylamine tests is:

• A

  $\mathrm{G}\mathrm{l}\mathrm{n}-\mathrm{A}\mathrm{s}\mathrm{p}$
• B

  $\mathrm{A}\mathrm{s}\mathrm{p}-\mathrm{G}\mathrm{l}\mathrm{n}$
• C

  $\mathrm{L}\mathrm{y}\mathrm{s}-\mathrm{A}\mathrm{s}\mathrm{p}$
• Correct answer
  D

  $\mathrm{S}\mathrm{e}\mathrm{r}-\mathrm{L}\mathrm{y}\mathrm{s}$

Solution

Serine $\Rightarrow$
Lysine $\Rightarrow$
Lysine has $-\mathrm{N}{\mathrm{H}}_2$ group hence gives $\oplus$ ve carbyl amine test and serine has $-\mathrm{O}\mathrm{H}$ group hence gives $\oplus$ ceric ammonium nitrate test.

Hence, the correct answer is option: 'D'.