5.1.1.18	L-serine = D-serine	-	-	
5.1.1.18	L-serine = D-serine	analysis of the catalytic reaction mechanism and intermediate stabilization in mammalian serine racemase using multiscale quantum-classical simulations, hybrid quantum mechanics/molecular mechanics molecular dynamics simulations in conjunction with umbrella sampling are performed, overview. The unprotonated pyridoxal 5'-phosphate-substrate intermediate is stabilized mostly due to solvation effects contributed by water molecules and active-site residues, as well as long-range electrostatic interactions with the enzyme environment	747090	
5.1.1.18	L-serine = D-serine	L-serine forms Schiff base with the cofactor pyridoxal 5'-phosphate, the free (non-pyridoxal 5'-phosphate cofactor binding) amino group of K56 is in the vicinity of the hydrogen on the Calpha atom, allowing the side chain of K56 to extract the proton away from the Ca atom and form a planar intermediate. the hydroxyl group of S84, on the re-face of this planar intermediate, donates its hydrogen to the Calpha atom of the intermediate resulting in the formation of D-serine. The subsequent attack of K56 on the cofactor forms the Schiff base and releases D-serine as the product. If the starting substrate is D-serine, S84 is likely to be protonated, favoring the extraction of hydrogen from the Calpha atom of pyridoxal 5'-phosphate-D-serine. The resulting planar intermediate allows K56 amino group to provide a proton from the si-face, restoring the L-serine intermediate. As a result, K56 reacts with pyridoxal 5'-phosphate to form the Schiff base and releases the L-serine as the final product. Catalytic mechanism, overview	728723	
5.1.1.18	L-serine = D-serine	racemase and dehydratase reaction mechanism of serine racemase, overview	704657	
5.1.1.18	L-serine = D-serine	reaction mechanism, overview	704350	
5.1.1.18	L-serine = D-serine	reaction mechanism, the enzyme catalyzes the racemization of serine, but also the alpha,beta-elimination of serine forming pyruvate. Mechanicistically, the racemization and alpha,beta-elimination reactions share the same intermediate, represented by a resonance-stabilized carbanion. The intermediate forms a partition between the two pathways. L-Serine binds to pyridoxal 5'-phosphate, yielding an external aldimine intermediate, followed by the abstraction of the alpha-proton by Lys56 and formation of a planar resonance-stabilized carbanion. At this point, protonation in the opposite side of the carbanion intermediate (mediated by the Ser84-OH group) generates D-serine. Since the proton abstraction and the reprotonation steps are performed by different residues (Lys56 and Ser84) that work as acid/base catalysts, serine racemase racemization is consistent with a two-base mechanism	747888	
5.1.1.18	L-serine = D-serine	reversible racemization and irreversible dehydration reactions are catalyzed by eukaryotic serine racemase, overview	746658	
5.1.1.18	L-serine = D-serine	SRR catalyses Ser racemization via a two-base mechanism in which two catalytic residues, Lys56 and Ser84 play vital roles in the abstraction and donation of alpha-proton of L-Ser and D-Ser, respectively	748126	
5.1.1.18	L-serine = D-serine	substrate recognition mechanism and catalytic mechanisms of both reactions, the racemization and the dehydration of serine, residues Lys57 and Ser82 located on the protein and solvent sides, respectively, with respect to the cofactor plane, are acid-base catalysts that shuttle protons to the substrate. Racemization mechanism via carbanion intermediate, alpha-aminoacrylate intermediate, and pyridoxal 5'-phosphate-lysine-D-alanine Schiff base	704535	
5.1.1.18	L-serine = D-serine	the abstraction and addition of alpha-hydrogen to L- and D-serine are conducted by residues K56 and S81 at the si- and re-sides, respectively, of pyridoxal 5'-phosphate, K56 functions as a residue that abstracts the alpha-hydrogen from the Schiff base intermediate, two-base catalytic mechanism, overview	726665