Discussion Forum



1)

A decapeptide (molecular weight 796) on complete hydrolysis gives glycine (molecular weight 75), alanine and phenylalanine. Glycine contributes 47 .0% of the total weight of hydrolysed products. The number of glycine units present in the decapeptide is


A) 6

B) 5

C) 4

D) 3

Answer:

Option A

Explanation:

A decapeptide has nine peptides (amide) linkages as

10122021393_g3.PNG

Therefore. no hydrolysis, it will absorb nine water molecules.Hence, the total mass of hydrolysis product=796+18 x9=958

$\Rightarrow$mass of glycine in hydrolysis product= $\frac{958 \times 47}{100}=450$

$\Rightarrow$ number of glycine molecule in one molecule of decapeptide=$\frac{450}{75}=6$