Characterization of a dimeric canine form of surfactant protein C (SP-C).
Canine pulmonary surfactant protein C (SP-C) is a small hydrophobic peptide which has one palmitoylated cysteine residue. SP-C enhances the insertion of phospholipids into a monolayer. Two forms of canine SP-C were isolated using Sephadex LH-60 chromatography. It was found that canine SP-C exists in a palmitoylated monomeric form of 3.5 kDa, and a non-acylated dimeric form of 7 kDa. Circular dichroism showed that both forms of SP-C exhibit similar secondary structures at the air/water interface. Both forms of SP-C were able to induce the insertion of phospholipids into a monolayer as measured with the Wilhelmy plate technique. In contrast to the palmitoylated monomeric form of SP-C, the non-acylated dimeric form of SP-C does not require calcium ions to insert phospholipids into a monolayer without the negatively charged phosphatidylglycerol. It is concluded that two forms of canine SP-C exist, but the physiological significance of these different forms remains to be established.
Creuwels
L A
LA
Laboratory of Veterinary Biochemistry, University of Utrecht, The Netherlands.
Demel
R A
RA
van Golde
L M
LM
Haagsman
H P
HP
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D002942:Circular Dichroism; D004285:Dogs; D010743:Phospholipids / Q000737:chemistry; D011312:Pressure; D017433:Protein Structure, Secondary; D011510:Proteolipids / Q000737:chemistry* / Q000302:isolation & purification; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000302:isolation & purification; D013499:Surface Properties
D010743:Phospholipids; D011510:Proteolipids; D011663:Pulmonary Surfactants