Structural requirements for activity

Many polysaccharides of eukaryotic origin show non-specific anti-viral activity and this property may be shared by some of the exopolysaccharides. The structural requirements for activity are not immediately evident as the polysaccharides exhibiting this activity are very diverse. 

Certain heterocycles will undoubtedly possess new and unexpected toxicities, yet most of the more esoteric ring systems have yet to be evaluated for toxicity in mammals. An example of how a rare toxicity is sometimes associated with an unusual heterocycle is provided by the potent neurotoxin (41), where relatively firm structural requirements for activity have been defined (76MI10502, 79MI10501). Within this context, the possible toxicity of compounds (42)-(44), for example, becomes interesting, but each of these are of unknown biological activity. Many other examples could be cited and can be readily identified by appropriate searches of the relevant sections of Chemical Abstracts (Sections 004 and 059). 

Here and later whether PNA is attached to N- or C-terminus of peptide depends on structural requirements for active peptide. Wrongly attached PNA can abolish peptide interactions with membrane or receptor. 

Chiba P, Ecker G, Schmid D, Drach J, Tell B, Goldenberg S, Gekeler V. Structural requirements for activity of propafenone type modulators in PGP-mediated multidrug resistance. Mol Pharmacol 1996 49 1122-30. 

The principal conclusion was that the structural requirements for activity were quite specific and that FMC 55626 apparently represented the most active compound in this class. 

Bruderlein, F. T., Humber, L. G., Voith, K. Neuroleptic agents of the benzocycloheptapyridoisoquinoline series. 1. Syntheses and stereochemical and structural requirements for activity of butaclamol and related compounds. J. Med. Chem. 1975, 18, 185-191. 

The general structural requirements for activity in the 1,4-dihydropyridine series are shown in Figure 3. Quite generally the following observations hold (43-49) ... 

Structural Requirements for Activity. It is of great importance to know the structural requirements for the activity of so powerful a substance as angiotensin. A summary of the work from our laboratory is contained in Figure 3. The hexapeptide is the minimum chain length for significant activity... 

Hollenberg, M.D., Saifeddine,M., Al-Ani, B. and Kawabata,A. (1997) Proteinase-activated receptors structural requirements for activity, receptor cross-reactivity, and receptor selectivity of receptor-activating peptides. Can. J. Physiol. Pharmacol. 75 832-841. 

One of the most important structural requirements for active nAChR effectors (neonicotinoids. Chapter 29.1) such as imidachloprid (6 1991, Gaucho ) [9] was the incorporation of chlorine in the 6-position of the pyridin-3-ylmethyl substituent of 5 [10]. 

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