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

Which one of the following is an example of a globular protein?

Identify the $N$-terminal and $C$-terminal $\alpha$-amino acids respectively in the following polypeptide fragment: $Ala-Gly-Ser-Tyr-Gly$.

Assume that a particular amino acid has an isoelectric point of $6.0$. In a solution of $pH$ $1.0$,which of the following species will predominate?

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 . . . . . . ?

Protein can be most easily removed from which of the following?