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GTPase activity associates with the inhibitory GTP‐binding regulatory component of adenylate cyclase purified from rat brain
Author(s) -
Enomoto Keiichi,
Asakawa Takeo
Publication year - 1984
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(84)80494-9
Subject(s) - gtpase , adenylate kinase , gtp' , cyclase , small gtpase , biochemistry , inhibitory postsynaptic potential , biology , microbiology and biotechnology , chemistry , enzyme , signal transduction , endocrinology
The inhibitory regulatory component of adenylate cyclase (N i ) was highly purified from rat brain synaptic membranes. A low K m GTPase activity was always associated with N i through the purification, and the recovery of GTPase activity correlated well with that of N i . Purified N i was hardly ADP‐ribosylated by islet‐activating protein (IAP). A heat‐labile factor in the fraction of the stimulative regulatory component (N s ) restored ADP‐ribosylation and also activated the GTPase about 2‐fold. NaF which was reported to interact with N i markedly reduced GTPase activity. The purified N i fraction inhibited adenylate cyclase only in the presence of a heat‐stable factor found in the partially purified regulatory component. GTPase and inhibitory activities were weak in myelin which contained only a small amount of N i . These findings support the view that GTPase activity is an intrinsic activity of N i and some factors are necessary for the function of N i .