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Bioassays peptide hormones

Methods to determine the potential biological activity of products obtained through recombinant DNA techniques are of fundamental importance. Despite the existence of numerous physicochemical techniques to characterize the protein product structure and the presence of contaminants, they provide little, if any, information about its biological potency. A bioassay is defined as a functional test, and no physicochemical test can measure the function. However, for some peptide hormones, which are less complex in structure than most cytokines, well defined physicochemical tests may be used to estimate biological activity for instance, the capillary electrophoresis analysis of a protein s isoform content if the specific activity of each one is known. [Pg.341]

Importantly, these mirror-image aptamers exhibited complete resistance against nuclease degradation, similar to the small-molecule-binding mirror-image aptamers previously selected by another group [15, 26]. When tested in a bioassay, the anti-vasopressin L-ssDNA-aptamer inhibited cAMP release mediated by vasopressin, but cAMP release induced by oxytocin (a related peptide hormone) was not affected. [Pg.325]

Fujita K, Nagaoka M, Komatsu Y, et al. (2003). Yeast pheromone signaling pathway as a bioassay to assess the effect of chemicals on mammalian peptide hormones. Ecotox. Environ. Safe. 56 358-366. [Pg.564]

In addition to the L. maderae myotropic peptides, a series of five myotropic peptides were isolated and structurally characterized from head extracts of the cricket, Acheta domesticus. with the same purification system and bioassay (Holman, G. M., et al. Chromatography and Isolation of Insect Hormones and Pheromones, in press.). The structures of these five myotropic peptides, the achetakinins, are shown in Table 1. Like the leucokinins, the achetakinins (Ak s) contain a C-terminal pentapeptide core which is responsible for the myotropic activity (12). In Ak s III and V, the C-terminal pentamer is the same as the leucokinin pentamer (Phe-X-Ser-Trp-Gly-NH2, where X = Asn, His, Ser, or Tyr) but in Ak s I, II, and IV a slightly different pentamer (Phe-X-Pro-Trp-Glv-NH is present. [Pg.45]

The final peptide structure shown in Table 2 represents an insect sulfakinin recently isolated from br-cc/ca extracts of the locust, Locusta migratoria. and structurally characterized. A modification of the four-step HPLC purification system (10) in which all gradients were extended to a higher final acetonitrile concentration was utilized. In addition, a C-8 reverse-phase column was substituted for the C-18 column (Schoofs, L., et al. Chromatography and Isolation of Insect Hormones and Pheromones, in press.). The isolated hindgut of L. maderae was used as the bioassay. Lom-SK contains residues of Leu and Ala at the 2- and 3-positions, respectively. The remainder of the sequence is identical with the 2-10 sequence of LSK-II. [Pg.46]

G12. Guyda, H. J., Corvol, M. T., Rappaport, R., and Posner, B. I., Radioreceptor assay for insulin-like peptides in human plasma Growth hormone dependence and correlation with sulfation activity by two bioassays. /. Clin. Endocrinol. Metab. 48, 739-747 (1979). [Pg.104]

The amount of these recoverable materials from the microorganisms is very small, when compared to the production of enzymes or secondary metabolites such as antibiotics. Thus, to convincingly demonstrate the presence of hormonal peptides in microorganisms the fermentation of large quantities of cells in defined medium was required as well as improved large scale extraction and purification procedures. In addition, we utilized very sensitive and specific radioimmunoassays and bioassays for detecting the low concentration of these materials. [Pg.177]

Despite the extremely low concentration of the hormone-like peptides in the microorganisms, we were able to detect them by very sensitive radioimmunoassays and bioassays which had previ-... [Pg.191]

Since almost all peptides were identified initially on the basis of bioassays, their names reflect these biologically assayed junctions (e.g., thyrotropin-releasing hormone and vasoactive intestinal polypeptide). A parsimonious view is that each peptide has unique messenger roles at the cellular level that are used repeatedly in functionally similar pathways within functionally distinct systems. [Pg.217]


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See also in sourсe #XX -- [ Pg.4 , Pg.52 ]

See also in sourсe #XX -- [ Pg.52 ]




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