Question

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

• A. Lys-Asp
• B. Ser-Lys
• C. Gln-Asp
• D. Asp-Gln

Answer 1

The correct option is B Ser-Lys

Correct option is (B)

$Serine\Rightarrow HO-\underset{o}{\underset{||}{C}}-\underset{N{H}_2}{\underset{|}{CH}}-C{H}_2-OH$
$Lysine\Rightarrow H_{2}N-C{H}_2-C{H}_2-C{H}_2-C{H}_2-\underset{N{H}_2}{\underset{|}{CH}}-\stackrel{o}{\stackrel{||}{O}}-OH$

Lysine has $-N{H}_2$ group hence gives positive carbyl amine test and serine has -OH group hence gives positive cerric ammonium nitrate test.