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Receptor‐binding capability of pancreatic phospholipase A 2 is separable from its enzymatic activity
Author(s) -
Ishizaki Jun,
Kishino Junji,
Teraoka Hiroshi,
Ohara Osamu,
Arita Hitoshi
Publication year - 1993
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(93)80149-o
Subject(s) - receptor , enzyme , phospholipase , phospholipase a2 , mutant , biochemistry , phospholipase a , binding site , chemistry , biology , stereochemistry , gene
Mammalian pancreatic phospholipase A 2 (PLA 2 ‐I) has its specific receptor through which PLA 2 ‐I induces a variety of biological responses. In this study, a fundamental relationship between the enzymatic and the receptor‐binding activities of PLA 2 ‐I was investigated. The specific binding of PLA 2 ‐I to the receptor was found to be independent of Ca 2+ which is requisite for the PLA 2 activity. On the basis of this observation, we designed and produced mutant PLA 2 ‐Is without Ca 2+ ‐binding abilities in order to demonstrate that the structural requirement for the enzymatic activity of PLA 2 ‐I is not identical with that for its receptor‐binding reaction. These mutant PLA 2 ‐Is lost almost all enzymatic activity through a disturbance at the Ca 2+ ‐binding site, as expected, but still retained a substantial affinity to the receptor, allowing us to conclude that the receptor‐binding reaction of PLA 2 ‐I is separable from its catalytic action.