Nitrous acid `(HNO_(2))` converts amino acids into hydroxy acids with retention of configuration. Estimation of nitrogen gas evolved in the reaction is the basis of Van slyke estimation of amino acids.
`R-overset(overset(NH_(2))(|))(CH)-COOH overset(HNO_(2))rarr R- overset(overset(OH)(|))(CH)-COOH + N_(2) uarr +H_(2)O`
Which of the following amino acids cannot be analysed by Van slyke method ?
(I) `HS-CH_(2)-overset(overset(NH_(2))(|))(CH)-COOH` (cysteine)

Options

A. only I
B. Only II
C. I & III
D. I,III,IV

Answer

B

Explanation

Since proline has `2^(@)` amino group.