Open AccessEvidence for an Adenylate‐Cyclase Activity in Neurosecretory Granule Membranes from Bovine Neurohypophysis
Author(s) -
BONNE Dominique,
NICOLAS Pierre,
LAUBER Marc,
CAMIER Maryse,
COHEN Paul,
TIXIERVIDAL Andrée
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11745.x
Subject(s) - adenylate kinase , cyclase , neurosecretion , membrane , granule (geology) , gtp' , enzyme , chemistry , fractionation , medicine , endocrinology , biophysics , biology , biochemistry , chromatography , paleontology
Purified bovine neurosecretory granules and their corresponding membranes were prepared after fractionation and purification processes from bovine pituitaries. An adenylate cyclase activity was detected both in the granules (apparent K m = 0.5 mM) and the corresponding preparations of the membranes (apparent K m = 0.5 mM). This enzyme was activated by fluoride in a way markedly dependent on the concentration of this ion, and with a maximum for a concentration of F − = 3.5 mM. The cyclase activity was also significantly enhanced by GTP. The reaction rate showed a strong dependance on the molar ratio [Mg 2+ ]/[ATP] with maximal velocity for 7. It is suggested that this activity might play an important role in the control and regulation of neurosecretion in the neurohypophysis.