The intracellular ratio of adenosine 3',5'-cyclic monophosphate (cyclic AMP) to guanosine 3',5'-cyclic monophosphate (cyclic GMP) may control the developmental pathway followed by antibody-forming cell (AFC) precursors. The evidence for this is derived from several different types of experiments. First lipopolysaccharide (LPS) which is mitogenic for B lymphocytes, stimulates rapid, transient ch...

Cyclic nucleotides and cyclic nucleotide-dependent protein kinases have been implicated in the regulation of cell motility and division, processes that depend on the cell cytoskeleton. To determine whether cyclic nucleotides or their kinases are physically associated with the cytoskeleton during cell division, fluorescently labeled antibodies directed against cyclic AMP, cyclic GMP, and the cyc...

• This review examines critically the evidence bearing on the hypothesis that the positive inotropic effects of catecholamines are mediated by intracellular cyclic adenosine monophosphate (cyclic AMP). The review is selective in several respects. For example, it does not contain extensive discussions about the biochemical actions of cyclic AMP, the enzymes regulating its synthesis and degradati...

we prove that each normal automorphism of the $n$-periodic product of cyclic groups of odd order $rge1003$ is inner, whenever $r$ divides $n$.

Evidence is available to suggest that Ca2+-calmodulin and cyclic nucleotides are involved in the regulation of ion transport in rabbit ileum. Since both Ca2+-calmodulin and cyclic nucleotides exert many of their effects by phosphorylation, the effects of Ca2+-calmodulin and cyclic nucleotides on phosphorylation of purified microvillus membrane from rabbit ileal mucosa were evaluated. Ca2+-calmo...

An assay for measuring 3’,5’-cyclic nucleotide phosphodiesterase activity over a wide range of substrate concentrations has been described. The ratio of cyclic adenosine 3’,5’monophosphate (cyclic AMP) to cyclic guanosine 3’,5’monophosphate (cyclic GMP) hydrolysis varied several fold among crude subcellular fractions from bovine and rat heart when measured at micromolar but not millimolar subst...

A low K,,, guanosine 3’:5’-monophosphate (cyclic GMP)specific phosphodiesterase was purified about 250-fold from crude extracts of the guinea pig lung by steps of DEAEcellulose chromatography, hydroxylapatite treatment, and preparatory polyacrylamide gel electrophoresis. Analytical gel electrophoresis revealed two protein bands, indicating that the enzyme preparation was about 50% homogeneous. ...

Two molecular species of repressible extracellular phosphodiesterases showing cyclic 2',3'and cyclic 3',5'-nucleotide phosphodiesterase activities were detected in mycelial culture media of wild-type Neurospora crassa and purified. The two molecular species were found to be monomeric and polymeric forms of an enzyme constituted of identical subunits having molecular weights of 50,000. This enzy...