610-68-4Relevant articles and documents
The detection of glycine from the treatment of glyoxylic acid with iron(II) sulfate and ammonia in water
Plater, M. John,Vassiliev, Ken
, p. 129 - 132 (2011)
A glycine/(NH4)2SO4 mixture was isolated by treatment of glyoxylic acid with FeSO4 and aqNH3 in H2O. The yields of glycine were estimated by 1H NMR. Pyruvic acid was not reduced to alanine under these conditions. This method for forming glycine might have occurred prebiotically alongside the Urey-Miller arc discharge method for making amino acids because glyoxylic acid is formed by arc discharge through a N2/CO2 atmosphere and both NH3 and Fe(II) occurred in the earth's early oceans. The carboxylic acid directs the reduction of 2,4-dinitrobenzoic acid to give 2-amino-4-nitrobenzoic acid.
Catalytic Mechanism of Cofactor-Free Dioxygenases and How They Circumvent Spin-Forbidden Oxygenation of Their Substrates
Hernández-Ortega, Aitor,Quesne, Matthew G.,Bui, Soi,Heyes, Derren J.,Steiner, Roberto A.,Scrutton, Nigel S.,De Visser, Sam P.
supporting information, p. 7474 - 7487 (2015/06/30)
Dioxygenases catalyze a diverse range of biological reactions by incorporating molecular oxygen into organic substrates. Typically, they use transition metals or organic cofactors for catalysis. Bacterial 1-H-3-hydroxy-4-oxoquinaldine-2,4-dioxygenase (HOD) catalyzes the spin-forbidden transfer of dioxygen to its N-heteroaromatic substrate in the absence of any cofactor. We combined kinetics, spectroscopic and computational approaches to establish a novel reaction mechanism. The present work gives insight into the rate limiting steps in the reaction mechanism, the effect of first-coordination sphere amino acids as well as electron-donating/electron-withdrawing substituents on the substrate. We highlight the role of active site residues Ser101/Trp160/His251 and their involvement in the reaction mechanism. The work shows, for the first time, that the reaction is initiated by triplet dioxygen and its binding to deprotonated substrate and only thereafter a spin state crossing to the singlet spin state occurs. As revealed by steady- and transient-state kinetics the oxygen-dependent steps are rate-limiting, whereas Trp160 and His251 are essential residues for catalysis and contribute to substrate positioning and activation, respectively. Computational modeling further confirms the experimental observations and rationalizes the electron transfer pathways, and the effect of substrate and substrate binding pocket residues. Finally, we make a direct comparison with iron-based dioxygenases and explain the mechanistic and electronic differences with cofactor-free dioxygenases. Our multidisciplinary study confirms that the oxygenation reaction can take place in absence of any cofactor by a unique mechanism in which the specially designed fit-for-purpose active-site architecture modulates substrate reactivity toward oxygen.
