Dataset Information

Cellular site and state combination of the adenosine 3':5'-cyclic monophosphate persisting after excitation of cerebral tissues.

ABSTRACT: 1. The subcellular distribution of cyclic AMP in guinea-pig cerebral-cortical tissue was determined before and after electrical stimulation, and after a period of continued incubation after electrical stimulation, with and without the presence of histamine. 2. Electrical stimulation and histamine increased the cyclic AMP content of all fractions, the greatest increase occurring in the supernatant fraction. 3. Continued incubation after cessation of electrical stimulation diminished the cyclic AMP of the total homogenate and supernatant fractions, but increased that of the synaptosomal fraction. 4. Further fractionation of the synaptosomal fractions from stimulated tissues suggested that most of their soluble cyclic AMP was in a higher-molecular-weight form than was that of the tissue supernatant. 5. It is suggested that protein binding and cytoplasmic transport of cyclic AMP are involved in the changes observed.

SUBMITTER: Newman M

PROVIDER: S-EPMC1183862 | biostudies-other | 1978 Jan

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:1. At least two classes of high-affinity cyclic AMP-binding proteins have been identified: those derived from cyclic AMP-dependent protein kinases (regulatory subunits) and those that bind a wide range of adenine analogues (adenine analogue-binding proteins). 2. In fresh-tissue extracts, regulatory subunits could be further subdivided into 'type I or 'type II' depending on whether they were derived from 'type I' or 'type II' protein kinase [see Corbin et al. (1975) J. Biol. Chem. 250, 218-225]. 3. The adenine analogue-binding protein was detected in crude tissue supernatant fractions of bovine and rat liver. It differed from the regulatory subunit of cyclic AMP-dependent protein kinase in many of its properties. Under the conditions of assay used, the protein accounted for about 45% of the binding of cyclic AMP to bovine liver supernatants. 4. The adenine analogue-binding protein from bovine liver was partially purified by DEAE-cellulose and Sepharose 6B chromatography. It had mol.wt. 185000 and was trypsin-sensitive. As shown by competition and direct binding experiments, it bound adenosine and AMP in addition to cyclic AMP. At intracellular concentrations of adenine nucleotides, binding of cyclic AMP was essentially completely inhibited in vitro. Adenosine binding was inhibited by only 30% under similar conditions. 5. Rat tissues were examined for the presence of the adenine analogue-binding protein, and, of those examined (adipose tissue, heart, brain, testis, kidney and liver), significant amounts were only found in the liver. The possible physiological role of the adenine analogue-binding protein is discussed. 6. Because the adenine analogue-binding protein or other cyclic AMP-binding proteins in tissues may be products of partial proteolysis of the regulatory subunit of cyclic AMP-dependent protein kinase, the effects of trypsin and aging on partially purified protein kinase and its regulatory subunit from bovine liver were investigated. In all studies, the effects of trypsin and aging were similar. 7. In fresh preparations, the cyclic AMP-dependent protein kinase had mol.wt. 150000. Trypsin treatment converted it into a form of mol.wt 79500. 8. The regulatory subunit of the protein kinase had mol.wt. 87000. It would reassociate with and inhibit the catalytic subunit of the enzyme. Trypsin treatment of the regulatory subunit produced a species of mol.wt. 35500 which bound cyclic AMP but did not reassociate with the catalytic subunit. Trypsin treatment of the protein kinase and dissociation of the product by cyclic AMP produced a regulatory subunit of mol.wt. 46500 which reassociated with the catalytic subunit. 9. These results may be explained by at least two trypsin-sensitive sites on the regulatory subunit. A model for the effects of trypsin is described.

Dataset Information

Cellular site and state combination of the adenosine 3':5'-cyclic monophosphate persisting after excitation of cerebral tissues.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets