Soluble and membrane-bound cyclic AMP diesterase activity with a low Michaelis constant in baker's yeast

Insulin and glucagon regulate the activation of two distinct membrane-bound cyclic AMP phosphodiesterases in hepatocytes.

Glucagon (10 nM) caused a transient elevation of intracellular cyclic AMP concentrations, which reached a peak in around 5 min, and slowly returned to basal values in around 30 min. When 1 mM-3-isobutyl-1-methylxanthine (IBMX) was present, this process yielded a Ka of 1 nM for glucagon. The addition of insulin (10 nM) after 5 min exposure to glucagon (10 nM) caused intracellular cyclic AMP conc...

آدنوزین منوفسفات حلقوی ( Cyclic AMP )

Comparison of rates of protein synthesis in skeletal muscle measured in vivo and in the perfused hemicorpus [proceedings].

where V, is the factor by which the maximal activity of the low-K, phosphodiesterase exceeds the cyclase activity, V, is the factor for the high-K,,, phosphodiesterase, and KL and KH are the K,,, values for the diesterases (Davies & William, 1975; Arch & Newsholme 1976). The equation gives lines of constant concentration of cyclic AMP on a plot of VH against VL (Fig. 1) . The combinations of VL...

Cyclic AMP responses are suppressed in mammalian cells expressing the yeast low Km cAMP-phosphodiesterase gene.

A genomic DNA fragment from Saccharomyces cerevisiae which contains the SRA5 (=PDE2) gene, coding for a low Km cAMP-phosphodiesterase, was transfected into Chinese hamster ovary cells. Clones carring the cAMP-phosphodiesterase gene were capable of growth in the presence of cholera toxin, which slows the growth of untransfected cells by elevating their cAMP levels. The cholera toxin-resistant tr...

Cyclic AMP and the plasma membrane potential in Neurospora crassa.

Diverse treatments, which have been shown by Slayman, C. L. (1977) in Water Relations in Membrane Transport in Plants and Animals (Jungreis, A., Hodges, T. K., Kleinzeller, A., and Schultz, S. G., eds) pp. 69-86, Academic Press, New York, to depolarize the plasma membrane of Neurospora, increase levels of adenosine 3':5'-monophosphate (cyclic AMP) in the organism. The treatments include those p...