W. F. Schmidt* and George Gassner Pages 502 - 510 ( 9 )
Physical and biological responses to natural and synthetic chemicals occur only at molecular distances and at molecular dimensions. Computational chemistry calculates results in molecular dimensions, but has serious difficulties in accurately predicting chiral interactions between diastereoisomers and/or enantiomers. Prediction of structures and conformations for more complicated chiral interactions such as in protein folding and protein binding may be intrinsically inaccurate because the molecular consequences of the forces between these spatially close chiral centers are not explicitly taken into account. Molecular forces are calculated within and between molecules by optimizing the variables of distance, shape, and time. Symmetry in space over a distance is not the same as symmetry in space over a period of time. Thus for asymmetrical chemical structures, time distorts the mirror of chirality. The physical chemical properties of unequal population of R-and S- isomers of any compound are not directly predictable from those of binary mixtures containing equal amounts of opposite isomers. Only if the corresponding populations of R- and S- isomers are exactly equal can molecular properties be explained by time independent variables. Ignoring time-dependent variables inherently precludes understanding time dependent conformational and configurational changes which occur in xenobiotics, hormones, peptides and other chiral compounds which occur in an asymmetrical chemical environment.