QSAR analysis has been performed for two sets of 4-hydroxypyridine derivatives, i.e. phenol type inhibitors of photosystem II, to find accurate quantitative models for their inhibitory potency in the Hill reaction. Separate QSAR models based either on the structural descriptors (molecular connectivity indices and other topological features) or on the physicochemical constants (pi, Vw, sigma) have been developed for the two sets of 4-hydroxypyridine derivatives. It was found that the size and lipophilicity of substituents at position 2 and 5 are the most important for the activity of derivatives with a long side chain. The electron-attracting capacity of these substituents might be an additional factor which increases the activity of 4-hydroxypyridines in the Hill reaction. However, the inhibitory potency of tetrahalogenated 4-hydroxypyridines depends on the type of halogen atom on the pyridine ring. The iodine substituent meets the receptor requirements best. The study suggests that the two groups of 4-hydroxypyridines analyzed have overlapping binding sites on the receptor protein.

Biologija,Kemija