Biological activity, prolonged

The activity of G protein Py subunits is modulated by another protein termed phosducin [16]. Phosducin is a cytosolic protein enriched in retina and pineal gland but also expressed in brain and other tissues. Phosducin binds to G protein Py subunits with high affinity. The result is prevention of Py subunit reassociation with the a subunit. In this way, phosducin may sequester Py subunits, which initially may prolong the biological activity of the a subunit. However, eventually this sequestration may inhibit G protein activity by preventing the direct biological... 

Darbepoetin alfa has a longer half-life than epoetin alfa and prolonged biologic activity. Doses are administered less frequently, starting at once a week when administered IV or SC. 

The three commercially available AmB formulations differ in their morphology, their composition, and, consequently, their biological activity. AmBisome (developed by Nexstar Pharmaceuticals, commercially available from Gilead Sciences) is a true liposome formulation, consisting of small, unilamellar vesicles (9). Their small size confers a prolonged circulation time... 

Experience so far from cUnical trials has shown these agents can be well tolerated at biologically active doses. However, cardiac toxicity, mainly QTC prolongation, and cardiac arrhythmias, including atrial fibrillation and tor-... 

Development of a-Melanotropln Analogs with Prolonged In Vitro and In Vivo Biological Activities... 

---