How many products are expected when the decapeptide VRVPVSQLQM is digested by an aminodipeptidase sp

[omatiy01]

How many products are expected when the decapeptide VRVPVSQLQM is digested by an aminodipeptidase specific for N-terminal valine?

A. Two products Your Answer

B. Three products

C. Four products Correct Answer

D. Ten products

Shouldn't the answer be 3? I think about it as n-terminus at the left side.

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[Neuroplasticity]

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[desperadoflakes]

I believe that this is one of those questions everybody is supposed to get wrong, but I'll take a shot. I think it's not coincidental that this is an aminoDIpeptidase, and we have a protein with valine every TWO residues starting from the amino-terminal. So I would infer that the function of this protein is to cleave off N-VX.

Cleavage 1) VR + VPVSQLQM
Cleavage 2) VP + VSQLQM
Cleavage 3) VS + QLQM
Total products: VR + VP + VS + QLQM

The tricky thing about this is that you think you're dealing with an enzyme that specifically cuts at the N-terminus side of a valine residue, in which you would only get 3 products. Seeing as how a dipeptidase is specifically an enzyme that cleaves dipeptides, I actually find this to be an unfair question.

 

[Neuroplasticity]

You are definitely correct.