Question

how many tripeptides (excluding stereoisomers) are possible by the glycine, valine, and aspartic acid in which nh2 group must be with chiral centre

Answer 1

Answer:

Hello

Since −COOH group is attached to alanine, one terminal of the tetrapeptide contains alanine. Thus, its position is fixed.

Glycine is achiral whereas valine and phenylalanine are chiral. Thus, −NH

2

group is attached to either valine or phenylalanine.

Thus following are the four possible combinations of the tetrapeptide.

H

2

N−Val−Gly−Phe−Ala−COOH

H

2

N−Val−Phe−Gly−Ala−COOH

H

2

N−Phe−Gly−Val−Ala−COOH

H

2

N−Phe−Val−Gly−Ala−COOH

Explanation:

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