Thus, although the EAA Ile is found at a higher frequency in primates than in cows (11.5 vs. 6.5%), the shift in composition appears to have occurred gradually (Figure 1). It is interesting that although none of the EAA were completely missing from this protein, the same was true for the NEAA. This is despite the fact that α-LA is a short polypeptide (~140 residues), so short that there was insufficient statistical signal to determine if the above changes in frequency were significant