Abstract
There exists the D-isomer of aspartate (D-Asp) in the mammalian body, not at trace levels but at high concentrations. The proportions of D-Asp to total aspartate in the mammalian tissues are approximately 5-70%. The contents of D-Asp in the tissues reveal unique changes during postnatal development, and D-Asp is specifically localized in the tissues. In addition, D-Asp does modulate hormonal secretion in the neuroendocrine and endocrine organs. Moreover, mammalian cells contain the molecular components for the biosynthesis, secretion, degradation and uptake of D-Asp. These lines of evidence suggest that D-Asp functions as a physiologically important biomolecule.
