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251.
Tj. B. van Wimersma Greidanus P. J. Lowry A. P. Scott Lesley H. Rees D. De Wied 《Hormones and behavior》1975,6(4):319-327
Recently purified melanocyte-stimulating hormones (MSH's) from dogfish pituitary tissue were tested on extinction of a conditioned avoidance response (CAR). Corticotrophin like intermediate lobe peptides (CLIP's) from dogfish and porcine origin were tested for an effect on avoidance extinction as well. All peptides appeared to delay extinction of the CAR.The results suggest that the pituitary contains various peptides which influence adaptive behavior. The observation that MSH is more potent in delaying extinction of the CAR then CLIP leads to the conclusion that the behavioral active sequence of the ACTH molecules is located in the N terminal part rather than in the C terminal part of the polypetide. 相似文献
252.
Cooperativity in ligand binding: a new graphic analysis. 总被引:16,自引:0,他引:16
When analyzing binding of ligands to macromolecules, the existence of site-site interactions complicates a straightforward interpretation of the binding parameters obtained through classical analytical methods, such as the Scatchard plot. For describing site-site interactions, we propose a new parameter, the of the receptor sites, , calculated as . Plotting as a function of fractional occupancy (), reveals that: (1) at very low occupancy a limiting high is obtained (e) (“empty sites” conformation); (2) when the fraction of sites filled increases above a certain threshold, begins to fall due to increasing site-site interactions until (3) a limiting low (f) is obtained (“filled sites” conformation). This method has been successfully applied to the negative cooperativity of insulin receptors. 相似文献
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The comparison of the proteins of rat liver rough membrane after stripping with EDTA or KCl-puromycin by two dimensional gel electrophoresis is described. By stripping the membrane with EDTA, most of the basic ribosomal proteins are still attached to the membrane; in contrast to the EDTA stripping method, treatment with KCl-puromycin removes most of the ribosomal proteins and does not remove any of the membranal proteins. 相似文献