Information concerning the fundamental mechanisms of action of both natural and environmental hormones, combined with information concerning endogenous hormone concentrations, reveals how endocrine-disrupting chemicals with estrogenic activity (EEDCs) can be active at concentrations far below those currently being tested in toxicological studies.
Among the designed series compounds 4c, 4f and 4j were found to be active at concentrations of 2 15 μg/ml.
Principles of design were formulated and examples of derivatives projected to be active at concentrations on the order of 10−7 M are proposed.
Additionally, the modified sortase was active at concentrations of urea up to 3 M and was capable of efficient catalytic protein protein coupling, as shown by the ligation of purified glutathione-S-transferase and green fluorescence protein.
Our present work therefore constitutes support for the existence of a eukaryotic AHL membrane receptor which is active at concentrations up to the micromolar range.
The potency of bombykol is comparable to that of RIF-1, which is active at concentrations ranging from 10-2 fM to 107 fM. 2) An expanded discussion of the difference in activity between purified RIF-1 vs. the sphingolipid-enriched fraction.
BPA did not cause a response on its own at either of these concentrations, though it has been observed to be active at other concentrations in this response [ 15, 19].
The intraarticular availability of adequate levels of IL-1ra is important, as IL-1β is considered to be active at low concentrations and relatively high levels of IL-1ra are required to inhibit the effects of IL-1β [ 29].
In porcine leukocytes, prophenins are amidated at the C-terminus [ 40, 41], and this extra positive charge may contribute to the binding of negatively charged targets; therefore, it is expected that the amidated version of the peptide tested in this study will be active at lower concentrations against T. vaginalis.
myo-Inositol 1,3,4,5,6-pentakisphosphate (InsP5, 2) has also been reported to have similar antiproliferative effects and to be active at lower concentrations (<50 μ m).[ 5] The mechanisms underlying the effects of applying InsP6 or InsP5 to cells (reviewed in ref. [ 4]) are not clear.
The relative abundance of these proteins, along with the structural proteins that are liberated from the nematocyst capsule during venom extraction, can mask the presence of lower abundance proteins that may be active at nanomolar concentrations (for example some snake venom serine proteases [ 38]).
