3672-03-5Relevant articles and documents
A point mutation converts dihydroneopterin aldolase to a cofactor-independent oxygenase
Wang, Yi,Scherperel, Gwynyth,Roberts, Kade D.,Jones, A. Daniel,Reid, Gavin E.,Yan, Honggao
, p. 13216 - 13223 (2008/03/11)
Dihydroneopterin aldolase (DHNA) catalyzes the conversion of 7,8-dihydroneopterin (1) to 6-hydroxymethyl-7,8-dihydropterin (4) in the folate biosynthetic pathway. Substitution of a conserved tyrosine residue at the active site of DHNA by phenylalanine converts the enzyme to a cofactor-independent oxygenase, which generates mainly 7,8-dihydroxanthopterin (6) rather than 4. 6 is generated via the same enol intermediate as in the wild-type enzyme-catalyzed reaction, but this species undergoes an oxygenation reaction to form 6. The conserved tyrosine residue plays only a minor role in the formation of the enol reaction intermediate but a critical role in the protonation of the enol intermediate to form 4.
Determination of Pterins in Biological Samples by Liquid Chromatography/Electrochemistry with a Dual-Electrode Detector
Lunte, Craig E.,Kissinger, Peter T.
, p. 1458 - 1462 (2007/10/02)
The pterins are a family of compounds that are currently of great interest in medicine and biology.Biopterin, in its reduced form, serves as the cofactor to the enzyme which catalyze the rate-limiting reactions in the biosynthesis of the catecholamines and serotonin.As such, it may serve a role in the regulation of the neurotransmitters.Abnormal pterin concentrations have been observed in the urine and serum of patiens with several diseases.No currently available analytical method is totally satisfactory for the determination of pterins in biological samples.They lack either specificity or the ability to detect both the oxidzed and reduced forms of the pterins.Liquid chromatography/electrochemistry (LCEC) using a dual-electrode detector can overcome both of these problems.A method has been developed that is capable of determining several pterin species and their various oxidation states in biological samples.The dual-electrode detector used in a parallel-adjacent configuration is also capable of enhancing peak identity assignments and selectively determining easily oxidized compounds in the presence of harder to oxidize compounds.