In which of the following processes does protein $NOT$ participate?

In an alkaline medium,glycine predominantly exists as/in a/an

The main structural feature of proteins is

The $pH$ at the isoelectric point of three amino acids are given as follows:

Amino acid	$pH$ at Isoelectric point
$(Amino \ acid)_{I}$	$6$
$(Amino \ acid)_{II}$	$9.8$
$(Amino \ acid)_{III}$	$3.9$

$(Amino \ acid)_{II}$ is . . . . . . ?

The $pK_a$ values for the three ionizable groups $X, Y$ and $Z$ of glutamic acid are $4.3, 9.7$ and $2.2$ respectively. The structure is $HO_2C-CH_2-CH_2-CH(NH_3^+)-CO_2H$. The isoelectric point $(pI)$ for this amino acid is:

The correct structure of Rhumann's Purple,the compound formed in the reaction of ninhydrin with proteins is :