Fritz Albert Lipmann (1899 –1986) was awarded half of the 1953 Nobel Prize in Physiology or Medicine for his discovery of coenzyme A and its importance for intermediary metabolism, in which energy is extracted from cellular nutrients and used to build cellular components. His early work included the identification of serine phosphate as the constituent of phosphoproteins, a group of proteins which are chemically bonded to a substance containing phosphoric acid, and an investigation into the Pasteur effect, which showed that oxygen inhibits fermentation in yeast and led to important discoveries on the mechanism of this reaction and on the role of glycolysis in the metabolism of cells in embryos. Lipmann's initial work on coenzyme A led him to investigate the role of phosphorylation in the intermediary reactions of biosynthesis. His later research included demonstrating that carbamoyl phosphate – a molecule involved in clearing the body from excess nitrogen in the urea cycle -- is a carbamoyl donor. He also explored the function of adenosine triphosphate in sulfate activation and investigated the biological mechanisms of peptide and protein synthesis.