In alanylglycylleucylalanylvaline the number of peptide linkages is: ______

The given peptide is: alanylglycylleucylalanylvaline. Since this sequence consists of the residues alanyl (Alanine), glycyl (Glycine), leucyl (Leucine), alanyl (Alanine) and valine, it is a pentapeptide containing 5 amino acid residues.

The number of peptide linkages (peptide bonds) in a peptide with $$n$$ amino acid residues is $$(n - 1)$$. Since it contains five residues, substituting into the formula yields:

$$ \text{Number of peptide linkages} = 5 - 1 = 4 $$

Therefore, the answer is 4.