A tetrapeptide has $$-$$COOH group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with $$-$$NH2 group attached to a chiral center is _______.
The substituents R1 and R2 for nine peptides are listed in the table given below. How many of these peptides are positively charged at pH = 7.0 ?
| Peptide | $${R_1}$$ | $${R_2}$$ |
|---|---|---|
| I | H | H |
| II | H | $$C{H_3}$$ |
| III | $$C{H_2}COOH$$ | H |
| IV | $$C{H_2}CON{H_2}$$ | $${(C{H_2})_4}N{H_2}$$ |
| V | $$C{H_2}CON{H_2}$$ | $$C{H_2}CON{H_2}$$ |
| VI | $${(C{H_2})_4}N{H_2}$$ | $${(C{H_2})_4}N{H_2}$$ |
| VII | $$C{H_2}COOH$$ | $$C{H_2}CON{H_2}$$ |
| VIII | $$C{H_2}OH$$ | $${(C{H_2})_4}N{H_2}$$ |
| IX | $${(C{H_2})_4}N{H_2}$$ | $$C{H_3}$$ |
A decapeptide (mol. wt. 796) 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 _________.
The total number of basic groups in the following form of lysine is
