Phoebus Levene (1869-1940), Russian biochemist. Levene was educated at St.Petersburg, but after obtaining his doctorate he emigrated to the USA. In 1909 Levene showed that the carbohydrate in yeast nucleic acid is ribose. In 1929 he showed that animal thymus nucleic acid is almost identical, but has one less oxygen; he called this deoxyribose. Levene suggested a simple tetranucleotide structure for RNA and DNA, with each of the four bases used just once in the structure. This would then be repeated to form a polynucleotide. Although wrong in this, Levene had at least shown that the nucleic acids were molecules independent of the proteins.