Phosphatidylcholine molecular species of calf lung surfactant.
Kahna, Miranda C., Gregory J. Andersonc, Walter R. Anyana, Stephen B.
Halla.
Division of Pulmonary and Critical Care Medicinea and Section of
Clinical Nutrition and Lipid Metabolismc, Department of Internal
Medicine, Oregon Health Sciences University, Portland, Oregon
APStracts 2:0111L, 1995.
This paper reports the detailed composition of molecular species of
the phosphatidylcholines (PC) in pulmonary surfactant from calves. PC
isolated by thin layer chromatography (TLC) was converted to
benzoylated diradylglyceride derivatives, which were separated by TLC
according to linkage group. Quantification of linkage groups by
analysis of total fatty acid content demonstrated that surfactant PC
contained 97.2% diacyl, 2.4% alkyl-acyl, and 0.4% alkenyl-acyl
compounds. The diacyl and alkyl-acyl diglyceride derivatives were
separated into individual molecular species by HPLC. Four major
species constituted 87% of the diacyl compounds. Dipalmitoyl
phosphatidylcholine (DPPC) was the most abundant constituent,
contributing 41% of the total PC. A second disaturated species,
palmitoyl-myristoyl PC (PMPC), also contributed an additional 12% of
total PC. At least 65% of PMPC occurred as the 1-palmitoyl-2
-myristoyl isomer, which has a lower melting point than the 1
-myristoyl-2-palmitoyl compound. These results show that most of
pulmonary surfactant PC is a relatively simple mixture, that numerous
minor compounds are present in small but possibly important amounts,
and that in surfactant from calves, the widely reported estimate that
DPPC constitutes 60% of surfactant PC is too large by 50%.
Received 3 June 1994; accepted in final form 1 June 1995.
APS Manuscript Number L154-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.