Protease inhibitory cyclic peptides

Protease inhibitors from a toxic waterbloom of the cyanobacterium Aplanktothrix rubescens. Grach-Pogrebinsky et al. in late 2003 reported the isolation and structural characterization of several novel protease inhibitory cyclic peptides and several known compounds isolated from a toxic waterbloom in Slovenian Lake Bled of the cyanobacterium Aplanktothrix rubescens. Long-range HMBC data were utilized... 

L-Mannitol was the starting material for synthesis of the orally available, non-peptidic HIV-1 protease inhibitory cyclic sulfone 300. Compound 299 was made by known methods (Vol. 11, p. 97) and iterative C-beaizylations (PhCHO/ Al(OPr-i)3 then NaBH4/Ni(Acac>2) then 0-alkylation and S-oxidation gave 300. ... 

Fig. 24.3. Schematic representation of a 5 enkephalinergic nerve terminal. (1) Pro-opioid proteins (proenkephalin A) are synthesized in the cell nucleus. (2) Pro-opioid proteins undergo microtubular transport to the nerve terminal. (3) Active endogenous opioids (E) are cleaved from the pro-opioid proteins by the action of processing proteases. (4) The active peptides (E) are taken up and stored in presynaptic vesicles. (5) The peptides are released when the presynaptic neuron fires. (6) The endogenous opioid peptides bind to postsynaptic receptors and activate second messenger systems. (7) For all opioid receptors, the second messenger effect is primarily mediated by a G-inhibitory (Gj/o) protein complex, which promotes the inactivation of adenylate cyclase (AC), a decrease in intracellular cyclic-adenosine-3, 5 -monophosphate (cAMP),...

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