BackgroundD-Serine. an endogenous co-agonist of the N-methyl-D-aspartate (NMDA) receptor. is synthesized from L-serine by serine racemase (SRR). Given the role of D-serine in both neurodevelopment and the pathophysiology of schizophrenia. https://www.markbroyard.com/hot-sale-us-topo-7-5-minute-map-for-sunken-lake-mi-supply-limited-grab/