Biological activity of complexes

The biological activity of complex multisubunit proteins is often regulated by allosteric interactions in which small ligands bind to the protein. Any change in the protein s activity is due to changes in the interactions among the protein s subunits. Effectors can increase or decrease the function of a protein. 

Natural product total synthesis has long served as a motivation for developing new chemical reactions. The converse, in which new reactions inspire efforts in natural product synthesis, is also widely observed. The work that is described in this chapter shows that these efforts can be symbiotic, and that this relationship can be useful for studying the biological activity of complex molecules. 

Absorption, metaboHsm, and biological activities of organic compounds are influenced by molecular interactions with asymmetric biomolecules. These interactions, which involve hydrophobic, electrostatic, inductive, dipole—dipole, hydrogen bonding, van der Waals forces, steric hindrance, and inclusion complex formation give rise to enantioselective differentiation (1,2). Within a series of similar stmctures, substantial differences in biological effects, molecular mechanism of action, distribution, or metaboHc events may be observed. Eor example, (R)-carvone [6485-40-1] (1) has the odor of spearrnint whereas (5)-carvone [2244-16-8] (2) has the odor of caraway (3,4). 

DETERMINATION OF THE FUNCTIONAL PROPERTIES OF THE BIOLOGICALLY ACTIVE PELOBISCHOFITE COMPLEX... 

The aim of the present work is to survey the results obtained by means of different equilibrium and structural measurements on the complexes formed with the various organotin(IV) cations. The biological activities of parent organotin(IV) and some of the complexes in object are also discussed. In the rest of the chapter, complexes of the organotin(IV) cations will be discussed — in most cases — in the following order ... 

D., Yang, C.-T, Ranford, J.D., Vittal, J.J. and Lee, P.F. (2003) Synthesis, characterization, and biological activities of 2-phenylpyridine gold(lll) complexes with thiolate ligands. Dalton Transactions, (17), 3376. 

Kilpin, K.J., Henderson, W. and Nicholson, B.K. (2007) Synthesis, characterisation and biological activity of cycloaurated organogold(III) complexes with imidate ligands. Polyhedron, 26, 204. 

Substituted thioureas have been extensively studied over the decades. Reaction of CoX2 (X = C1, Br) with substituted phenylthioureas yield a range of complexes involving halide and thiourea as ligands, characterized by spectroscopy and thermogravimetric analysis.503 Both [Co(Rtu)4(OH2)2]2+ (Rtu = thiourea, phenylthiourea, allylthiourea) and [Co(Rtu)2(OH2)4]2+ (Rtu = diphenylthiourea) have been prepared and characterized as low-spin octahedral species.504 The octahedral bis(phenylthiourea)bis(dithiolate)cobalt(II) complex, one of a number of complexes of phenylthiourea, chlorophenylthiourea and bis(diphenylphospinothioyl)methane prepared and characterized,505 proved the most biologically active of those tested. 

Alberto, R. Motterlini, R. Chemistry and biological activities of CO-releasing molecules (CORMs) and transition metal complexes. Dalton Trans., 1651-1660 (2007). 

Schatzschneider, U. Photoactivated Biological Activity of Transition-Metal Complexes. Eur. J. Inorg. Chem. 2010,1451-1467 (2010). 

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