Lung surfactant synthesis: a Ca++-dependent microsomal phospholipase A2 in the lung
A Garcia, JD Newkirk, RD Mavis - Biochemical and Biophysical Research …, 1975 - Elsevier
A Garcia, JD Newkirk, RD Mavis
Biochemical and Biophysical Research Communications, 1975•ElsevierWe present the first direct evidence for a highly active, Ca++-dependent phospholipase A 2
in the microsomal fraction of rat lung homogenate. Several previously reported studies from
other laboratories strongly implicate this enzyme as a key metabolic step in the biosynthesis
of dipalmitoyl lecithin, the primary component of pulmonary surfactant. In the present study,
stoichiometric amounts of [3 H] lysophosphatidylethanolamine and [14 C] fatty acid were
released during incubation of 1-[9, 10-3 H] palmitoyl-2-sn-[1′-14 C] linoleoyl …
in the microsomal fraction of rat lung homogenate. Several previously reported studies from
other laboratories strongly implicate this enzyme as a key metabolic step in the biosynthesis
of dipalmitoyl lecithin, the primary component of pulmonary surfactant. In the present study,
stoichiometric amounts of [3 H] lysophosphatidylethanolamine and [14 C] fatty acid were
released during incubation of 1-[9, 10-3 H] palmitoyl-2-sn-[1′-14 C] linoleoyl …
Abstract
We present the first direct evidence for a highly active, Ca++-dependent phospholipase A2 in the microsomal fraction of rat lung homogenate. Several previously reported studies from other laboratories strongly implicate this enzyme as a key metabolic step in the biosynthesis of dipalmitoyl lecithin, the primary component of pulmonary surfactant. In the present study, stoichiometric amounts of [3H]lysophosphatidylethanolamine and [14C]fatty acid were released during incubation of 1-[9, 10-3H]palmitoyl-2-sn-[1′-14C]linoleoyl phosphatidylethanolamine with the lung microsomal fraction. Marker enzyme measurements showed that the microsomal activity cannot be due to contamination with mitochondria, which also show phospholipase A2 in both lung and liver. In contrast, liver microsomes show predominantly a phospholipase A1 activity.
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