ABSTRACT
Figure 5-7 Molecular structures of selected synthetic phospholipid analogs used in lung surfactant research. Compounds shown are diether and ether-amide phosphonolipids (DEPN or EAPN series) synthesized by Turcotte, Notter, and co-workers [651, 657-659, 673, 1091-1093]. Synthetic analogs of this kind can be used to study structure-activity correlates for phospholipid-like molecules or as novel constituents for synthetic exogenous surfactants. DEPN compounds have two identical palmitylether chains; EAPN compounds have one palmitylether chain and one palmitoylamide chain. Analogs 10-13 in both series are shown in the protonated form existing near neutral pH. Many other synthetic phospholipid analogs are also available for research applications. (Redrawn from Ref. 657.)
human SP-B are available, as are regional and full length SP-C peptides. Examples of several N-terminal human sequence SP-B peptides are illustrated in Figure 5-8. Also studied are derivatized SP-B and SP-C peptides with specific amino acid substitutions and deletions, plus SP-C peptides with acyl moieties of varying length attached covalently at selected locations. Less specific synthetic peptides are also used in lung surfactant research, including KL4, a 21 amino acid peptide containing repeating subunits with one lysine (K) and four leucine (L) residues that is combined with DPPC, palmitoyl-oleoyl-PG (POPG), and palmitic acid as a synthetic exogenous surfactant [142-144, 730] (Chapter 14). Examples of other nonspecific hydrophobic synthetic peptides include synthetic homopolymers of valine, phenylalanine, leucine, or other hydrophobic amino acids [1118] and synthetic amphipathic α-helical peptides [711-713, 1225].
