How many unique structures can be formed from a peptide hydrolyzed into three different tripeptides with no shared amino acids?

• A. 3
• B. 4
• C. 6
• D. 27

Answer: (C)

To determine how many unique structures can be formed from a peptide hydrolyzed into three different tripeptides with no shared amino acids, consider the nature of tripeptides and their formation from distinct amino acids.

When a peptide is broken down into tripeptides, and it's specified that no amino acids are shared among these tripeptides, we start by noting that a tripeptide consists of three amino acids linked by peptide bonds. Given that we have three different tripeptides, each comprising three distinct amino acids, we can think about the arrangement of these amino acids within the tripeptide.

Let’s denote the three different amino acids as A, B, and C. The way these three amino acids can be sequenced or arranged into tripeptides matters because the order of amino acids in a protein can drastically influence its function.

The mathematical formula used to determine the number of unique arrangements of n different items is given by n!, which is the factorial of n. For three distinct amino acids, we calculate:

• The arrangements of three distinct amino acids (A, B, C) would be 3!, which equals 3 × 2 × 1 = 6.

Thus, each unique arrangement corresponds to a different tripe