The amino-acid chains are also subject to such inflation. A chain of two amino acids could display 202, or 20 × 20, or 400 possible combinations, since each of the twenty protein-forming amino acids could combine with any one of that same group of twenty in the second position of a short peptide chain. With a three-amino-acid sequence, we’re looking at 203, or 8,000, possible sequences. With four amino acids, the number of combinations rises exponentially to 204, or 160,000, total combinations, and so on.

