-transparent.png){kind=logo}
The extracellular adenosine 3',5'-cyclic monophosphate phosphodiesterase (3',5'-cyclic-nucleotide 5'-nucleotidohydrolase, EC 3.1.4.17) produced by Dictyostelium discoideum has two kinetic forms. The free enzyme has a Km of approximately 10 microM. The second form is the result of a complex formed with a heat-stable inhibitor and has a Km in the millimolar range. Treating the enzyme-inhibitor complex with dithiothreitol stimulated enzyme activity 20- to 100-fold and changed in Km from millimolar to micromolar. Dithiothreitol inactivated the inhibitor. Reconstituting purified enzyme with excess inhibitor returned the Km to the millimolar range. Under conditions known to inhibit the production of extracellular inhibitor or in mutants that lack it, extracellular phosphodiesterase activity was already high and could not be increased by dithiothreitol. The phosphodiesterase and inhibitor sedimented at 6 S and 3 S, respectively; the enzyme-inhibitor complex sedimented at 6.7 S.
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
May 1979,
Biochimica et biophysica acta,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
February 1976,
Journal of general microbiology,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
January 1974,
Methods in enzymology,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
January 1983,
Journal of biochemistry,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
October 1978,
Developmental biology,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
January 1971,
Biochemical and biophysical research communications,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
April 1976,
Cell differentiation,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
March 1981,
Cell differentiation,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
January 1972,
Biochemical and biophysical research communications,
R H Kessin, and
S J Orlow, and
R I Shapiro, and
J Franke
January 1984,
Biochimica et biophysica acta,
