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...

Adenosine 3':5' -monophosphate (cyclic AMP) -dependent protein kinase from bovine heart muscle catalyzes the phosphorylation of its regulatory, cyclic AMP-binding subunit. Phosphorylation enhances net dissociation of the enzyme by cyclic AMP. Chromatography on omega-aminohexyl-agarose was used to study the effects of phosphorylation on cyclic AMP binding and subunit dissociation and reassociati...

A series of polynitrogen molecules composed by multiple cyclic-N(3) and/or cyclic-N(5) are systematically investigated by using DFT and MP2 methods. It is found that all energetically favored structures appear with a corner to corner connection between two rings for the cyclic-N(3) and/or the cyclic-N(5). Furthermore, straight interaction between the N(3)-rings would decrease the stability of c...

• 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...

As a generalization of cyclic codes, quasi-cyclic codes contain many good linear codes. Extensive search is made and lots of good quasi-cyclic codes are obtained from irreducible cyclic codes. A new binary [95, 13, 40] code which improves the lower bound on the minimum distance, is also constructed. Index Term — Codes and coding, linear codes, cyclic codes, idempotent, irreducible codes, quasi-...