nonpolar amino acid

non·po·lar a·mi·no ac·id

an α-amino acid in which the functional group attached to the α-carbon (that is, R in RCH(NH3+)COO-) has hydrophobic properties, for example, valine, leucine.
References in periodicals archive ?
In sickle cell anemia, these glutamic acids are replaced by valines, large nonpolar amino acids.