Search PubMed⌕ Search

Biomedical subjects

C D Barry

Publications and source records attributed to C D Barry.

15 recordsLinked to original sources
PubMed1978

Elucidation of the receptor-bound conformation of the enkephalins.

The biologically relevant conformers of enkephalin predicted by solid state, solution state, and theoretical energy studies have been compared with the published structure-activity data on these compounds. No conformational technique proposes a model consistent with all the pharmacological data; the shortcomings of each approach are evaluated. An alternative approach, which correlates the structure-activity data of opiate compounds with that of the enkephalins, is described and shown to produce a model consistent with the available structure-activity data.

Endorphins↗
PubMed1978

Alloxan stimulation and inhibition of insulin release from isolated rat islets of Langerhans.

The rate of alloxan-induced insulin release was measured from rat islets maintained in a simple perifusion system. Insulin release during the five-minute exposure to alloxan reached its maximum rate after two to three minutes of the exposure and then rapidly declined. This insulin release was dependent upon extracellular calcium and was associated with an increased 45Ca uptake by isolated islets. Once exposed to alloxan, however, the islets did not release insulin when stimulated again with D-glucose or alloxan. These effects of alloxan on insulin release (stimulation and subsequent inhibition) and the increased 45Ca uptake were prevented by the presence of 3-0-methyl-D-glucose during the alloxan exposure. These findings indicate a close correlation between alloxan-induced insulin release and the subsequent inhibition of further insulin release. D-glucose, when present during the entire five-minute exposure to alloxan, protected competitively against alloxan inhibition of insulin release. In addition, D-glucose, when present immediately after brief (one to three minutes) alloxan exposures, reversed some of the subsequent inhibition of insulin release. These findings suggest that alloxan and D-glucose were competing for a common site on the beta-cell. The possibility of this site being a receptor responsible for the initiation of insulin release is discussed.

Alloxan↗
PubMed1975

The predicted structure of the calcium-binding component of troponin.

The structure prediction of the calcium binding component of troponin (TN-C) incorporates the following assumptions: (1) TN-C contains four regions homologous to the calcium binding "EF hand" of parvalbumin. (2) The four EF hands are arranged in two pairs with overall symmetry, 222. (3) The regions of the calcium binding component of troponin which are not in the four EF hands connect the hands within each pair, one to two and three to four, and connect the pairs, region two to region three. In the resulting model there is a well-defined hydrophobic core made from side chains of all eight helical regions and of the four calcium binding loops. The Ca2+ within pairs are separated by 11 A; while the pairs of Ca2+ are separated from one another by over 30 A. Cys-98 and Tyr-109 are suggested to be sensitive spectroscopic probes. Calcium(1) is suggested to be solvent accessible and most readily replaced by a lanthanide. Because of the overall symmetry of the calcium binding component of troponin, one can anticipate that the inhibitory- and the tropomyosin binding components of troponin are similar to one another.

Albumins↗