Apr 17
Chemistry Department Seminar: Jonathon Sweedler
The amino acids (except glycine) occur in two forms because of the possibility of forming two different enantiomers (stereoisomers) around the central carbon atom. Until recently, animals were thought to contain only L-amino acids, which predominate in nature as they are the main components of proteins. The development of novel analytical methods has revealed that D-amino acids are present in many organisms such as invertebrates and vertebrates, and that some of D-amino acids have important physiological functions. A range of measurement tools are described to characterize D-amino acids. These tools include capillary electrophoresis and capillary liquid chromatography separations as these approaches can characterize the chemical content of small brain regions down to individual neurons. Using these approaches, a number of questions are addressed: where are D-amino acids in the brain? How are they formed? What do they do? Using capillary electrophoresis with laser induced fluorescence and mass spectrometry detection, we have determined specific neurons that synthesize D-aspartate, and have measured the formation, transport and release of D-aspartate in a stimulation dependent manner. Thus, our data supports that D-aspartate is a neurotransmitter. Other D-amino acids including D-serine, D-alanine and D-glutamate are found in specific brain and endocrine regions and may have different functions. Newer data on the presence of a range of D-amino acids in neurons and endocrine structures are highlighted, including their activity-dependent release and potential physiological functions.