Rationalizing the solution properties of zwitterions by means of computational chemistry.

This short review describes our computational studies of carnitine, acetylcarnitines, and betaines over the past two decades. Interspersed among the three computational studies--a molecular mechanics study of the conformer population of carnitine and acetylcarnitine, an AM1 study of the energetics of hydrolysis of acetylcarnitine, and an HF 6-31G* study of the solvation energies and structures of a homologous series of betaines--are brief overviews of our research in designing and testing new therapeutic agents for non-insulin dependent diabetes and for protection against sexually transmitted diseases. The three studies also show how computational chemistry has evolved during this time to enable an evaluation of the structure and energetics of zwitterions in aqueous solution.