The helical hydrophobic moments and surface activities of serum apolipoproteins

The mean helical hydrophobic moments (muH) have been used to compare the amphipathic helices of several apolipoprotein classes with the helices in membrane proteins, water-soluble globular proteins and surface-active peptides. The amphipathic helices in serum apolipoproteins have similar muH and mean hydrophobicities to helices in water-soluble globular proteins. The intrinsic surface activities of proteins and peptides, as determined by surface pressure at the air/water interface, correlate with the product (muH . F) where muH is the average value of muH for all helices in the molecule, and F is the fraction of alpha-helix structure in the protein.