948-60-7

Usage

Uses

Pterine-6-carboxylic Acid is a degradation product of Folic acid (F680300).

Purification Methods

The acid gives yellow crystals by repeated dissolution in aqueous NaOH and adding aqueous HCl. It has UV with max at 235, 260 and 265nm ( 11,000, 10,500 and 9,000) in 0.1N HCl and 263 and 365nm ( 20,500 and 9,000) in 0.1N NaOH. [UV: Pfleiderer et al. Justus Liebigs Ann Chem 741 64 1970, Stockstad et al. J Am Chem Soc 70 5 1948, Fluorescence: Kavanagh & Goodwin Arch Biochem 20 315 1949, Beilstein 26 III/IV 4053.]

InChI:InChI=1/C7H5N5O3/c8-7-11-4-3(5(13)12-7)10-2(1-9-4)6(14)15/h1H,(H,14,15)(H3,8,9,11,12,13)

Upstream product

• 1004-75-7 2,5,6-triamino-3,4-dihydro-4-pyrimidinone 
• 116140-94-4 ethyl 2-bromo-3,3-diethoxypropionate 
• 712-30-1 6-formylpterin 
• 120930-09-8 7,8-dihydro-6-(2-furyl)pterin 
• 716-74-5 2,4-diamino-pteridine-6-carboxylic acid 
• 110-65-6 1,4-dihydroxybut-2-yne 
• 7218-52-2 4-hydroxy-2-butynoic acid 
• 623-11-0 1-methyl-4-nitrosobenzene 
• 54-62-6 aminopterin 
• 712-29-8 2-amino-4-hydroxy-6-hydroxymethylpteridine 
• 940953-51-5 2-amino-4-butoxy-6-2'-acetoxy-1'-oxopropylpteridine 
• 940953-52-6 2-amino-4-butoxy-6-2'-tetrahydropyran-2-yloxy-1'-oxopropylpteridine 
• 940953-42-4 2-amino-4-butoxy-6-2'-hydroxy-1'-oxopropylpteridine 
• 19962-30-2 N-(6-methyl-4-oxo-1,4-dihydropteridin-2-yl)acetamide 

Downstream Products

• 2236-60-4 2-aminopteridin-4(3H)-one 

Relevant academic research and scientific papers

Photochemistry of 6-formylpterin in alkaline medium

6-formylpterin solutions at pH 11 were photolyzed at 350 nm at room temperature. The photochemical reactions were followed by UV/VIS spectrophotometry, thin layer chromatography (TLC), and high-performance liquid chromatography (HPLC). In the presence of oxygen, 6-carboxypterin is the only photoproduct detected by the analytical techniques mentioned. In the absence of oxygen, a new compound showing an absorbance maximum at 480 nm is observed. The latter compound is thermally oxidized very fast in the presence of oxygen to 6-carboxypterin. The quantum yields of substrate disappearance and of photoproduct formation are reported.

Electron transfer mediated decomposition of folic acid by photoexcited dimethoxophosphorus(V)porphyrin

A water soluble porphyrin, dimethoxophosphorus(V)tetraphenylporphyrin (MP(V)TPP) photosensitized folic acid decomposition in aqueous solution, resulting in the formation of a strongly fluorescent pteridine compound. The quantum yield of folic acid decomposition by photoexcited MP(V)TPP could be determined by a flurometry. A possible mechanism of the initial process of this photodecomposition is direct oxidation through an electron transfer from folic acid to the excited singlet state of MP(V)TPP. It is considered that this electron transfer proceeds as a diffusion-controlled reaction. The quantum yields of the electron transfer and the following process of folic acid decomposition could be determined. In deuterium oxide, folic acid decomposition through the photosensitized singlet oxygen generation by MP(V)TPP was also observed. A fluorometry based on the formation of a strong fluorescent compound through the oxidized decomposition of folic acid may be applied to evaluate the biomolecule damaging-activity of photosensitizers. In addition, a protocol of this assay is proposed. This simple photosensitized reaction in aqueous solution may be used for a first screening of a photosensitizer for phototherapy.

Photochemical behavior of Safranine-Riboflavin complex in the degradation of folic acid

The photochemistry of safranine complexed with riboflavin and the photoinduced electron transfer from folic acid to the complex were investigated by steady-state and time resolved absorption spectroscopy, and the photoproducts were further analyzed by LC-orbitrap-FT-MS. UV-vis spectra of the complex showed a decrease in the safranine band at 520 nm with increasing concentration of riboflavin, which was attributed to complex formation. A 1:1 (safranine:riboflavin) stoichiometry was determined using Job's method. Following safranine photoexcitation, there is formation of a radical pair in the complex by donation of an electron from ground-state riboflavin to excited-state safranine. The cation radical of riboflavin within this complex reacts with folic acid to yield FA+?, which may accept an electron from the anion radical of safranine, avoiding the photobleaching of the safranine. In contrast, the reaction of the anion radical of non-complexed safranine with folic acid leads to safranine photobleaching.

Effect of pterin impurities on the fluorescence and photochemistry of commercial folic acid

Folic acid, or pteroyl?L?glutamic acid (PteGlu) is a conjugated pterin derivative that is used in dietary supplementation as a source of folates, a group of compounds essential for a variety of physiological functions in humans. Photochemistry of PteGlu is important because folates are not synthesized by mammals, undergo photodegradation and their deficiency is related to many diseases. We have demonstrated that usual commercial PteGlu is unpurified with the unconjugated oxidized pterins 6?formylpterin (Fop) and 6?carboxypterin (Cap). These compounds are in such low amounts that a normal chromatographic control would not detect any pterinic contamination. However, the fluorescence of PteGlu solutions is due to the emission of Fop and Cap and the contribution of the PteGlu emission, much lower, is negligible. This is because the fluorescence quantum yield (ΦF) of PteGlu is extremely weak compared to the ΦF of Fop and Cap. Likewise, the PteGlu photodegradation upon UV-A radiation is an oxidation photosensitized by oxidized unconjugated pterins present in the solution, and not a process initiated by the direct absorption of photons by PteGlu. In brief, the fluorescence and photochemical properties of PteGlu solutions, prepared using commercially available solids, are due to their unconjugated pterins impurities and not to PteGlu itself. This fact calls into question many reported studies on fluorescence and photooxidation of this compound.

Photoinactivation of tyrosinase sensitized by folic acid photoproducts

Tyrosinase catalyzes in mammals the first and rate-limiting step in the biosynthesis of the melanin, the main pigment of the skin. Pterins, heterocyclic compounds able to photoinduce oxidation of biomolecules, accumulate in the skin of patients suffering from vitiligo, where there is a lack of melanin. Folic acid (PteGlu) is a conjugated pterin widespread in biological systems. Aqueous solutions of tyrosinase were exposed to UV-A irradiation (350 nm) in the presence of PteGlu and its photoproducts (6-formylpterin and 6-carboxypterin). The reactions were followed by UV-Vis spectrophotometry, enzyme activity measurement, fluorescence spectroscopy and HPLC. In this work, we present data that demonstrate unequivocally that solutions of tyrosinase exposed to UV-A irradiation in the presence of PteGlu, undergo enzyme inactivation. However, PteGlu itself causes a negligible effect on the activity of the enzyme. In contrast, PteGlu photoproducts are efficient photosensitizers. The tyrosinase inactivation involves two different pathways: (i) a photosensitization process and (ii) the oxidation of the enzyme by the hydrogen peroxide produced during the photooxidation of PteGlu and its photoproduct. The former pathway affects both the active site and the tryptophan residues, whereas the latter affects only the active site. The biological implications of the results are discussed.

Photochemistry of dihydrobiopterin in aqueous solution

Dihydrobiopterin (H2Bip) and its oxidized analogue, biopterin (Bip), accumulate in the skin of patients suffering from vitiligo, a chronic depigmentation disorder in which the protection against UV radiation fails. The photochemistry of H2Bip was studied in neutral aqueous solutions upon UV-A irradiation (320-400 nm) at room temperature. The photochemical reactions were followed by UV/vis spectrophotometry, HPLC and enzymatic methods for hydrogen peroxide (H2O2) determination. Photoproducts were analyzed by means of electrospray ionization mass spectrometry. Under anaerobic conditions, excitation of H2Bip leads to the formation of at least two isomeric dimers with molecular masses equal to exactly twice the molecular mass of the reactant. This reaction takes place from the singlet excited state of the reactant. To the best of our knowledge, this is the first time that the photodimerization of a dihydropterin is reported. In the presence of air, the dimers are again the main photoproducts at the beginning of the reaction, but a small proportion of the reactant is converted into Bip. As the reaction proceeds and enough Bip accumulates in the solution, a photosensitized process starts, where Bip photoinduces the oxidation of H2Bip to Bip, and H 2O2 is formed. As a consequence, the rates of H 2Bip consumption and Bip formation increase as a function of irradiation time, resulting in an autocatalytic photochemical process. In this process, Bip in its triplet excited state reacts with the ground state of H 2Bip. The mechanisms involved are analyzed and the biological implications of the results are discussed. The Royal Society of Chemistry 2010.

New results on the photochemistry of biopterin and neopterin in aqueous solution

New photochemical studies of the reactivity of biopterin (BPT) and neopterin (NPT) in acidic (pH = 5.5) and alkaline (pH = 10.5) aqueous solutions at 350 nm and room temperature were performed. The photochemical properties of BPT are of particular interes

Chemoselective oxidation of 6-hydroxyalkylpteridine and its application to synthesis of 6-acyl-7,8-dihydropteridine

Alcohol-selective oxidation of 6-l′-hydroxyalkylpteridines catalyzed by ruthenium (IV), RuO4-, gives 6-acylpteridines in high yields. Partial reduction of the products affords 6-acyl-7,8-dihydropteridine derivatives, such as a lipophilic derivative of sepiapterin, deoxysepiapterin, and sepiapterin-C.

Influence of human serum albumin on photodegradation of folic acid in solution

It has been proposed that photodegradation of folates may be the reason for the pigmentation of races living under high fluence rates of ultraviolet radiation. The photodegradation of folic acid (FA) induced by ultraviolet-A (UV-A) radiation, in solution and in the presence of human serum albumin (HSA), was studied with absorption and fluorescence spectroscopy. FA photodegradation, with formation of p-aminobenzoyl-L-glutamic acid, 6-formylpterin and pterin-6-carboxylic acid, was found to follow an exponential trend. A scheme of FA photodegradation, which involves photosensitization of FA degradation by its photoproducts, was proposed. The rate of FA photodegradation decreased drastically in the presence of HSA, whereas the spectral characteristics of the photoproducts remained constant. The reduction of the FA photodegradation rate by HSA was accompanied by degradation of tryptophan in HSA. Tryptophan, when added to solutions of FA, had a similar effect as HSA. In solutions of FA and HSA the FA photoproducts cause photodamage mainly to HSA rather than to FA itself. The oxygen dependence of FA photodegradation and the inhibition of this process by sodium azide indicate that singlet oxygen may participate in the photosensitizing activity of FA photoproducts.

Photoinduced formation of reactive oxygen species from the acid form of 6-(hydroxymethyl)pterin in aqueous solution

The photochemistry of 6-(hydroxymethyl)pterin (HPT; 1) in aqueous solution (pH 5-6) was investigated by irradiation at 350 nm at room temperature. The photochemical reactions of the acidic form 1a were followed by UV/VIS spectrophotometry, thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and enzymatic methods for the determination of the superoxide anion radical (O2.-) and hydrogen peroxide (H2O2). When 1a is exposed to UV-A radiation, the intermediates 4 and 4′ are formed reacting with O2 to yield 6-formylpterin (FPT; 5) and 6-carboxypterin (CPT; 6). under formation of O 2.- and H2O2 (Scheme 3). The quantum yields of the disappearance of HPT (1a) and of the formation of the photoproducts 5 and 6 were determined. HPT was investigated for its efficiency in singlet-oxygen (1O2) production in acidic aqueous solution. The corresponding quantum yield of 1O2 production (ΦΔ) was 0.15±0.02, as measured by the 1O2 luminescence in the near-IR (1270 nm) upon continuous excitation of the sensitizer. However, 1O2 does not participate in the actual photooxidation of HPT (1a) to FPT (5) and CPT (6).