Lucinactant is a new synthetic peptide-containing surfactant for intratracheal use. It contains sinapultide, a novel, hydrophobic, 21-amino acid peptide (leucine and lysine repeating units, KL4 peptide) designed to mimic human surfactant protein-B (SB-P). More specifically, it mimics the C-terminal amphipathic helical domain of this protein. It also consists of phospholipids (dipalmitoylphosphatidylcholine, DPPC and palmitoyloleoyl phosphatidylglycerol, POPG) and a fatty acid (palmitic acid). It is completely devoid of animal-derived components.
CAT No: 10-101-168
CAS No:138531-07-4
Synonyms/Alias:Sinapultide;138531-07-4;Kl4 peptide;ATI 01;KL4 (peptide);Sinapultida;Sinapultide [USAN:INN];UNII-040X3AX99T;PEPTIDE KL4;PEPTIDE KL-4;RWJ 45652;ATI-01;DTXSID30160707;040X3AX99T;RWJ-45652;SINAPULTIDE (MART.);SINAPULTIDE [MART.];L-Lysine, L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-;L-Lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysyl-L-leucyl-L-leucyl-L-leucyl-L-leucyl-L-lysine;Sinapultidum;SINAPULTIDE [MI];SINAPULTIDE [INN];SINAPULTIDE [USAN];SCHEMBL180504;CHEMBL2103901;DTXCID3083198;AT42478;DB11332;DA-67594;NS00124788;
Sinapultide, also known as synthetic surfactant protein B (SP-B) analog, is a laboratory-engineered peptide that mimics the function of natural pulmonary surfactant proteins. Designed to enhance surface activity and stability, Sinapultide demonstrates amphipathic properties, allowing it to interact effectively with lipid monolayers and facilitate the reduction of surface tension in aqueous environments. Its unique structural features, including a helical conformation and hydrophobic domains, make it particularly effective in biophysical and biochemical research related to respiratory systems. The synthetic origin of Sinapultide ensures batch-to-batch consistency, making it a reliable tool for scientific investigations where reproducibility is critical. Researchers value its ability to integrate with phospholipid mixtures, offering a versatile model for studying surfactant-associated phenomena and membrane dynamics.
Respiratory Physiology Research: Sinapultide serves as a pivotal component in the study of alveolar surface tension and lung mechanics. By incorporating this peptide into lipid-based surfactant models, scientists can investigate the mechanisms underlying lung compliance, gas exchange efficiency, and the prevention of alveolar collapse. Its role in mimicking the function of endogenous surfactant proteins enables detailed exploration of pulmonary biophysics, contributing to the development of improved artificial surfactant formulations and a deeper understanding of respiratory function at the molecular level.
Surfactant Replacement Studies: The synthetic SP-B analog is widely employed in the evaluation and optimization of exogenous surfactant preparations. Researchers utilize Sinapultide to assess the efficacy and stability of various lipid-peptide mixtures under dynamic conditions, such as compression-expansion cycles that simulate breathing. Through these studies, insights are gained into the critical factors that influence surfactant spreading, adsorption, and resilience to inactivation by plasma proteins or other inhibitory substances, thereby informing the design of next-generation surfactant therapies for laboratory and preclinical use.
Membrane Biophysics and Lipid Interaction: In the field of membrane biophysics, Sinapultide is instrumental in elucidating the interactions between peptides and phospholipid bilayers. Its amphipathic and helical structure allows for detailed analysis of peptide insertion, orientation, and aggregation within lipid environments. By serving as a model system, Sinapultide aids in the characterization of membrane fluidity, surface pressure modulation, and the formation of lipid-peptide complexes, offering valuable data for both basic and applied research in membrane science.
Drug Delivery System Development: The ability of Sinapultide to enhance the spreading and stability of phospholipid films positions it as a valuable component in the design of novel drug delivery systems. Researchers explore its incorporation into liposomal or nanoparticle-based carriers to improve the dispersion, retention, and bioavailability of encapsulated therapeutic agents. Its surfactant-like properties facilitate the uniform distribution of drug formulations across biological membranes, making it a subject of interest for those developing advanced delivery technologies for pulmonary and other routes.
Biomaterials and Surface Coating Research: Synthetic surfactant protein B analogs are increasingly investigated for their potential in biomaterials science, particularly in the modification of surface properties for medical devices and tissue engineering scaffolds. By leveraging the surface-active and biocompatible nature of Sinapultide, scientists aim to create coatings that resist protein fouling, promote cellular adhesion, or enhance the integration of implants with host tissues. These studies contribute to the advancement of functional biomaterials with improved performance and longevity in biomedical applications.
Lipid-Protein Interaction Mechanism Studies: Sinapultide continues to be indispensable in fundamental research focused on the mechanisms of lipid-protein interactions. Its well-defined sequence and structural motifs serve as a template for dissecting how peptides modulate the organization, dynamics, and mechanical properties of lipid assemblies. Such investigations not only expand our knowledge of pulmonary surfactant biology but also inform broader research into membrane-associated processes relevant to cell signaling, fusion, and transport, thereby positioning Sinapultide as a cornerstone in the study of complex biological interfaces.
KL4, a 21-residue peptide containing repeating KLLLL subunits, represents one of the early synthetic surfactant peptides designed to roughly reflect the overall ratio of cationic to hydrophobic amino acids found in native SP-B (22). Despite an early demonstration of SP-B-like activity and the fact that KL4 is currently under evaluation for FDA approval for clinical use as the peptide component of the synthetic exogenous surfactant Surfaxin (Lucinactant), surprisingly little is known about the specific effects of KL4 on phospholipid interfacial film behavior during compression/expansion and collapse.
KL4 Peptide Induces Reversible Collapse Structures on Multiple Length Scales in Model Lung Surfactant
KL4 ([lysine-(leucine)4]4-lysine) is a synthetic peptide based on SP-B structure and is the major constituent of Surfaxin®, a potential therapeutic agent for respiratory distress syndrome in premature infants. There is, however, no clear understanding about the possible lipid-KL4 interactions behind its function, which is an inevitable knowledge to design improved therapeutic agents. To examine the phase behavior, topography, and lipid specificity of KL4/lipid systems, we aimed to study different surfactant model systems containing KL4, neutral dipalmitoylphosphatidylcholine (DPPC) and/or negatively charged dipalmitoylphosphatidylglycerol (DPPG) in the presence of Ca2+ ions. Surface pressure-area isotherms, fluorescence microscopic images, scanning force microscopy as well as time-of-flight secondary ion mass spectrometry suggest that KL4 is not miscible with DPPC and therefore forms peptide aggregates in DPPC/KL4 mixtures; that KL4 specifically interacts with DPPG via electrostatic interactions and induces percolation of DPPG-rich phases; that existing DPPG-Ca2+ interactions are too strong to be overcome by KL4, the reason why the peptide remains excluded from condensed DPPG domains and passively colocalizes with DPPC in a demixed fluid phase; and that the presence of negatively charged lipid is necessary for the formation of bilayer protrusions. These results indicate that the capability of the peptide to induce the formation of a defined surface-confined reservoir depends on the lipid environment, especially on the presence of anionic lipids.
The Surfactant Peptide KL4 in Lipid Monolayers
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