The discovery of biological enantioselectivity: Louis Pasteur and the fermentation of tartaric acid, 1857--a review and analysis 150 yr later.

Nearly a decade after discovering molecular chirality in 1848, Louis Pasteur changed research direction and began investigating fermentations. Conflicting explanations have been given for this switch to microbiology, but the evidence strongly suggests that Pasteur's appointment in 1854 to the University of Lille--an agricultural-industrial region where fermentation-based manufacturing was of great importance--and an appeal for help in 1856 by a local manufacturer experiencing problems in his beetroot-fermentation-based alcohol production played a significant role. Thus began, in late 1856, Pasteur's pioneering studies of lactic and alcoholic fermentations. In 1857, reportedly as a result of a laboratory mishap, he found that in incubations of ammonium (+/-)-tartrate with unidentified microorganisms (+)-tartaric acid was consumed with considerable preference over (-)-tartaric acid. In 1860, he demonstrated a similar enantioselectivity in the metabolism of tartaric acid by Penicillium glaucum, a common mold. Chance likely played a significant role both in Pasteur's shift to microbiology and his discovery of enantioselective tartrate fermentations, but he rejected pure serendipity as a significant factor in experimental science and in his own career. Pasteur's milestone discovery of biological enantioselectivity began the process that in the long run established the fundamental importance of molecular chirality in biology.

Historical aspects of nitrate therapy.

The exciting story of the development of nitrates as drugs in clinical medicine is briefly reviewed. Glyceryl trinitrate (nitroglycerin) was synthesised by Sombrero in 1847. Amyl nitrite was discovered a few years later and was used by Guthrie in 1859. The first report on the action of glyceryl trinitrate and amyl nitrite was published by Brunton in 1867, and further papers were published by Murell in 1879. Organic nitrates appeared in the 1930s. Krantz and co-workers synthesised and used mannide dinitrate, which was longer acting than the nitrates that had been used previously. Research on a similar drug, isosorbide dinitrate, was initiated by Porjé in Stockholm. The drug was first marketed in Sweden in 1946. Isosorbide dinitrate was independently synthesised in the United States by Harris and colleagues in the 1950s. The drug was used fairly extensively on both sides of the Atlantic. However, there was a temporary decrease in popularity around 1970 when Needleman and colleages reported oral nitrates to be of questionable value, as they underwent rapid biotransformation during first-pass metabolism in the liver. This opinion was later altered and today the drug enjoys worldwide acceptance in different formulations. Also, in recent years one of the active metabolites, isosorbide 5-mononitrate, has been marketed as an effective antianginal drug.