The d-serine transport system in Escherichia coli K-12 was studied by use of a mutant unable to form d-serine deaminase, yet resistant to d-serine. The mutant is greatly impaired in its ability to accumulate d-serine, d-alanine, and glycine. Transport of l-alanine is partially affected but transport of l-serine is unaffected. The mutant is also resistant to d-cycloserine, indicating that d-seri...

Non-enzymatic deamination of serine and cysteine is catalyzed by pyridoxal and certain metal salts at 100” (2). This finding suggested that pyridoxal phosphate might be involved in the enzymatic deamination of these amino acids. Vitamin B, has already been implicated in the desulfhydration of cysteine by rat liver (3) and of cysteine and homocysteine by bacteria (4). Several similarities of cys...

Serine racemase (SR), localized to astrocytic glia that ensheathe synapses, converts L-serine to D-serine, an endogenous ligand of the NMDA receptor. We report the activation of SR by glutamate neurotransmission involving alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors via glutamate receptor interacting protein (GRIP) and the physiologic regulation of cerebellar granule cell ...

Glial cells are increasingly recognized as active players that profoundly influence neuronal synaptic transmission by specialized signaling pathways. In particular, astrocytes have been shown recently to release small molecules, such as the amino acids l-glutamate and d-serine as "gliotransmitters," which directly control the efficacy of adjacent synapses. However, it is still controversial whe...

Sphingolipids are a diverse group of lipids with important roles in beta-cell biology regulating insulin folding and controlling apoptosis. Sphingolipid biosynthesis begins with the condensation of L-serine and palmitoyl-CoA. Here we tested the effect of L-serine supplementation on autoimmune diabetes development and blood glucose homeostasis in female NOD mice. We found that continuous supplem...

Tryptophanase, L-tryptophan indole-lyase with extremely absolute stereospecificity, can change the stereospecificity in concentrated diammonium hydrogenphosphate solution. While tryptophanase is not inert to D-serine in the absence of diammonium hydrogenphosphate, it can undergo L-tryptophan synthesis from D-serine along with indole in the presence of it. It has been well known that tryptophana...

L-Serine dehydratase (SD) was produced to the extent of only 0·04 international unit (iu) per mg dry weight by Aeromollas pUllctata NRRL B-928 when grown on a chemically defined medium. Addition of 2% (w/v) L-serine to this medium increased SD ten-fold or more, indicating a significant inductive effect. o-Serine was toxic to the organism, making weights and enzyme titres uncertain, but DL-serin...