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A tetrapeptide has -COOH group on alanine. This products glycine (Gly), valine (Val), phenylalanine (Phe) and alanine(Ala), on complete hydrolysis. For this tetrapeptide , the number of possible sequences (primary structures) with -NH_(2) group attached to a chiral centre is |
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Answer» (a)`CH_(3)-overset(CH_3)overset(|)(CH)-overset(NH_2)overset(|)(CH)-COOH"""Valine (Val)"` (b)`CH_(3)-overset(NH_2)overset(|)(CH)-COOH"""Alanine (Ala)"` (c)`C_(6)H_(5)-CH_(2)-overset(NH_2)overset(|)(CH)-COOH"""Phenylalanine (PHE)"` (d) `H_(2)N-CH_(2)-CO_(2)H "" "Glycine (Gly)"` Since alanine is the end amino ACID and glycine does not contain a chiral CENTRE. therefore , all tetrapeptides begin either with valine or with phenylalanine. THUS , the following four tetrapeptides are possible : (i)Val -Phe- Gly-Ala (II) Val-Gly-Phe-Ala (iii) Phe- Val-Gly-Ala (iv) Phe-Gly-Val-Ala |
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