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Adenylate cyclase in cilia from Paramecium
Author(s) -
Schultz Joachim E.,
Klumpp Susanne
Publication year - 1983
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(83)80180-x
Subject(s) - cyclase , paramecium , adenylate kinase , vesicle , egta , percoll , biochemistry , calmodulin , gtp' , chemistry , biophysics , biology , membrane , enzyme , calcium , centrifugation , organic chemistry
A particulate adenylate cyclase was identified in the excitable ciliary membrane from Paramecium tetraurelia . MnATP was preferentially used as substrate, the K m was 67 μM, V max was 1 nmol cAMP.min −1 .mg −1 , a marked temperature optimum of 37°C was observed. Adenylate cyclase was not inhibited by 100 μM EGTA or 100 μM La 3+ , whereas under these conditions guanylate cyclase activity was abolished. Fractionation of ciliary membrane vesicles by a Percoll density gradient yielded two vesicle populations with adenylate cyclase activity. In contrast, calmodulin/Ca‐dependent guanylate cyclase was associated with vesicles of high buoyant density only.