Which of the following is the least likely to be involved in stabilising the three-dimensional folding of most proteins?

How many of the given compounds will give a positive Biuret test____?

Glycine, Glycylalanine, Tripeptide, Biuret

 In alanylglycylleucylalanylvaline the number of peptide linkages is:

Monomeric subunits of proteins can sometimes assemble into higher order assemblies. Two such related human proteins $\mathrm{P}$ and $\mathrm{Q}$assemble into hexamers by sequential assembly of their subunits. However, while $\mathrm{P}$ assembles into a hexameric ring.$\mathrm{Q}$ assembles into a linear hexameric arrangement as shown in the figure. Only hexameric assemblies of the proteins are functional.

The equilibrium constants for association $\left({\mathrm{K}}_1,{\mathrm{K}}_2,{\mathrm{K}}_3\right.$, and $\left.{\mathrm{K}}_4\right)$ of subunits at each step until pentamers are assembled, both for $\mathrm{P}$ and $\mathrm{Q}$, are the same $\left({10}^5\right)$. However, the equilibrium association constant of the final step of assembly into a hexamer is drastically different, ${10}^{10}$ for $P$ and ${10}^5$ for $\mathrm{Q}$. Based on this information, choose the statement(s) that is(are) likely to be true.

Following tetrapeptide can be represented as

($\mathrm{F},\mathrm{L},\mathrm{D},\mathrm{Y},\mathrm{I},\mathrm{Q},\mathrm{P}$ are one letter codes for amino acids)