Surfactant Protein B (SP-B)

There are four surfactant-specific proteins, designated surfactant protein A (SP-A), SP-B, SP-C and SP-D respectively. SP-A and SP-D are hydrophilic surfactant proteins and are members of the collectin family. SP-B and SP-C are hydrophobic surfactant proteins and may be the most appropriate indicators for the evolutionary origin of surfactant. SP-B is synthesized by the alveolar type II epithelial cells as a 40-42 kD precursor that is subsequently proteolytically processed to 7.8-8 kD. SP-B enhances the spreading and stability of surfactant phospholipids in the alveolus. SP-B is essential for air-breathing in mammals and is therefore largely conserved. SP-B can interact with both phospholipid head groups and fatty chains and is particularly active in enhancing surface active behavior in endogenous and exogenous lung surfactants. Even low SP-B contents had measurable effects in increasing the adsorption, dynamic surface tension lowering, and/or film respreading of DPPC, mixed synthetic lipids, and column-purified lung surfactant phospholipids. Deficiency of SP-B and other surfactant components is associated with respiratory distress syndrome (RDS) in premature infants and adults with respiratory distress syndrome (ARDS). Applications: Suitable for use in ELISA, Western Blot, and Immunohistochemistry. Other applications not tested. Recommended Dilutions: Western Blot: 1:50. Recognizes proteins of 42, 25 and 18kD under non-reducing conditions. The 18kD form is reduced to 7.7-8kD in the presence of beta-mercaptoethanol. Immunohistochemistry (Frozen, paraffin): 1:50 Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.