Question

You want to test pentapeptides (short peptides with only five amino acids) for their ability to bind to and inhibit a particular receptor. To do this, you set out to synthesize all possible pentapeptides and test each individually. Assuming you’ll use just the 20 common amino acids, how many different pentapeptides will you have to test for receptor binding

Answer 1

Answer:

The correct answer is 3200000.

Explanation:

If there is only one amino acid in the peptide, the probable number of combinations would be 20. If there is only two amino acid in the peptide, the probable number of combinations will be 20^2. Similarly, for three amino acids in the peptide it would be 20^3 and for four it would be 20^4.  

Thus, in the case of pentapeptide, that is, five amino acids in a peptide, the probable number of combinations will be 20^5, which comes out to be 3200000. Thus, the total number of different pentapeptides will be 3200000 that needs to be tested for receptor binding.