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Permeability changes of phospholipid liposomes caused by pancreatic phospholipase A 2 : analysis by means of phase transition release
Author(s) -
Okimasu Eiji,
Shiraishi Noriyuki,
Kobayashi Sumio,
Morimoto Yasuko M.,
Miyahara Masanobu,
Utsumi Kozo
Publication year - 1982
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(82)81211-8
Subject(s) - medical school , phospholipid , emergency department , chemistry , medicine , medical education , biochemistry , psychiatry , membrane
Many biological messages are recognized by the binding of the ligands to specific receptors of the outer surface of the cell membrane [l-4]. These bindings then initiate certain chemical and physical changes in the membrane. One of the early changes in membrane state is the activation of phospholipase A2 (PLA2) [5]. This reaction has many important functions such as in biosynthesis of prostaglandins, in physicochemical changes of biomembranes and in regulation of the activities of other membrane bound enzymes. Therefore, the activation of membrane bound PLA2 has a key role in the mechanisms of cell activation. One of the important features of the regulation of PLA2 is the dependency of activation on membrane structure. Many investigations were carried out on the analogies with much better defined systems using soluble phospholipase, though this system is essentially different from those occurring in natural membranes. In those studies, it was proposed that a particular region of PLA2, so called interface recognition site, is involved in interaction with phospholipid structure [6]. Moreover, it was considered that phosphatidylcholine can be hydrolysed only near the transition temperature where lipid in liquid crystalline phase and in the gel phase coexist ]7,81. We have therefore applied the phase transition release technique to the study of the activation mechanism as related to the changes in physiological characteristics of the membrane and bring evidence that the maximal carboxyfluorescein release Phospholipase A2 (Phospholipid liposome) Dipalmitoylphosphatidylcholine