Biomaterial Database

Pulmonary surfactant protein SP-A with phospholipids in spread monolayers at the air-water interface. 1995

S Taneva, and T McEachren, and J Stewart, and K M Keough

Department of Biochemistry, Memorial University of Newfoundland, St. John's, Canada.

Spread monolayers of pulmonary surfactant protein SP-A, alone or mixed with phospholipid(s), were formed at the air-water interface. Binary monolayers of SP-A plus dipalmitoylphosphatidylcholine (DPPC) showed positive deviations from ideal behavior of the mean areas in the films consistent with partial miscibility and interaction between the protein and lipid. During compression of SP-A/DPPC films which contained > or = 5 wt % SP-A, properties were displayed which were consistent with the protein being partially squeezed out at surface pressures of about 30 mN/m. Some protein appeared to remain in the monolayers even when they were compressed to high surface pressures of about 65-70 mN/m, and it was possibly included in the collapse phase(s) that was (were) formed at 72 mN/m. During dynamic cyclic compression-expansion of SP-A/DPPC monolayers initially formed at low surface pressures, SP-A enhanced the respreading of the films compressed beyond collapse compared to the respreading after collapse of films containing DPPC alone. Spread monolayers of SP-A plus either dipalmitoylphosphatidylglycerol (DPPG) or a mixture of DPPC plus DPPG (7:3, mol/mol) displayed additivity of the mean areas in the films, consistent with complete immiscibility (or ideal miscibility, an unlikely effect) between the protein and lipid components. Electrostatic repulsion between SP-A and DPPG, both negatively charged at physiological pH, possibly governed the behavior of these lipid-protein films. Calcium ions in the subphase did not alter the properties of SP-A/DPPC films, whereas they improved the ability of SP-A to mix with DPPG and DPPC/DPPG. Binding of calcium to the negatively charged DPPG and SP-A may account for association of the protein with DPPG and DPPC/DPPG in the monolayers in the presence of the divalent ions.

UI	MeSH Term	Description	Entries
D009994	Osmolar Concentration	The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.	Ionic Strength,Osmolality,Osmolarity,Concentration, Osmolar,Concentrations, Osmolar,Ionic Strengths,Osmolalities,Osmolar Concentrations,Osmolarities,Strength, Ionic,Strengths, Ionic
D010715	Phosphatidylglycerols	A nitrogen-free class of lipids present in animal and particularly plant tissues and composed of one mole of glycerol and 1 or 2 moles of phosphatidic acid. Members of this group differ from one another in the nature of the fatty acids released on hydrolysis.	Glycerol Phosphoglycerides,Monophosphatidylglycerols,Phosphatidylglycerol,Phosphatidyl Glycerol,Glycerol, Phosphatidyl,Phosphoglycerides, Glycerol
D011510	Proteolipids	Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.
D011663	Pulmonary Surfactants	Substances and drugs that lower the SURFACE TENSION of the mucoid layer lining the PULMONARY ALVEOLI.	Surfactants, Pulmonary,Pulmonary Surfactant,Surfactant, Pulmonary
D006023	Glycoproteins	Conjugated protein-carbohydrate compounds including MUCINS; mucoid, and AMYLOID glycoproteins.	C-Glycosylated Proteins,Glycosylated Protein,Glycosylated Proteins,N-Glycosylated Proteins,O-Glycosylated Proteins,Glycoprotein,Neoglycoproteins,Protein, Glycosylated,Proteins, C-Glycosylated,Proteins, Glycosylated,Proteins, N-Glycosylated,Proteins, O-Glycosylated
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000388	Air	The mixture of gases present in the earth's atmosphere consisting of oxygen, nitrogen, carbon dioxide, and small amounts of other gases.
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures