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Characterization of the membrane‐associated GTPase activity: Effects of chemotactic factors and toxins
Author(s) -
Pelz Claudia,
Matsumoto Tadashi,
Molski Thaddeus F. P.,
Becker Elmer L.,
Sha'afi Ramadan I.
Publication year - 1989
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240390211
Subject(s) - gtpase , pertussis toxin , concanavalin a , cholera toxin , chemotaxis , g protein , gtp' , leukotriene b4 , intracellular , biology , chemistry , biochemistry , microbiology and biotechnology , endocrinology , enzyme , signal transduction , receptor , immunology , in vitro , inflammation
Membranes prepared from rabbit neutrophils exhibit GTPase activity which can be stimulated by the chemotactic factor fMet‐Leu‐Phe. The maximum contribution of the ATPase activities to the basal and the fMet‐Leu‐Phe‐stimulated GTPase activities are less than 20% and 9%, respectively. The basal GTPase activity has a V max = 34.2 ± 1.3 (pmol/mg protein, min) and a K m = 0.39 ± 0.03 μM; and the fMet‐Leu‐Phe‐stimulated has a V max = 52.3 ± 2.5 (pmol/mg protein, min), and a K m = 0.29 ± 0.02 μM. The GTPase activity can be stimulated by fMet‐Leu‐Phe and leukotriene B 4 . Unlike these two chemotactic factors, concanavalin A does not stimulate this GTPase activity. In addition, the rise in intracellular concentration of free calcium produced by concanavalin A is not inhibited by pertussis toxin treatment. Both the basal and stimulated GTPase activities are affected by pertussis toxin, cholera toxin and N‐ethylmaleimide.