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Calcium inhibition of a heat‐stable cyclic nucleotide phosphodiesterase from Neurospora crassa
Author(s) -
Shaw Nicholas M.,
Harding Roy W.
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)80399-8
Subject(s) - neurospora crassa , egta , cyclic nucleotide phosphodiesterase , phosphodiesterase , calmodulin , calcium , chemistry , enzyme , cyclic nucleotide , biochemistry , nucleotide , organic chemistry , mutant , gene
Neurospora crassa had a heat‐stable (up to 95°C), soluble cyclic nucleotide phosphodiesterase (PDE). Both unheated and heat‐stable PDE activities were inhibited by micromolar concentrations of Ca 2+ . This inhibition was reversed by EGTA or EDTA in molar excess of the Ca 2+ concentration. Calmodulin was not involved in the Ca 2+ inhibition, nor was Ca 2+ inhibition of the heat‐stable PDE due to cleavage inactivation of the enzyme by a Ca 2+ ‐stimulated protease. In addition to Ca 2+ , several other cations inhibited the activity of the heat‐stable enzyme. Cyclic AMP and cGMP, but not 2′3′ cAMP were substrates for both unheated and heat‐stable PDEs. This is the first report of a PDE which is inhibited by micromolar concentrations of Ca 2+ .