Question

A decapeptide (Mol. Wt. 769) on complete hydrolysis gives glycine (Mol. Wt. 75), alanine and phenylalanine.
Glycine contributes `47.0 %` to the total weight of the hydrolysed products. The number of glycine units. Present in the decapeptide is.
A. 4
B. 5
C. 6
D. 7

Answer 1

Correct Answer - C
Mol . Wt . Of decapeptide =796 u
Number of water molecules used for hydrolysis of decapeptide =9
i.e., Decapeptide +`9H_(2)O to ` glycine +alanine +Phenylalanine
Total weight of amino acids obtained after addition of 9 molecules of water
=796+9x 18 =958 u
Now total weight of glycine in the hydrolysed product `=(958xx47)/100 =450.26 u`
But mol. wt. of glycine =75 u
`:.` No of glycine units in decapaptide `450.26/75 =6`