氨基磺酸应用于甘蔗渣预处理的研究

本研究尝试将氨基磺酸应用于甘蔗渣预处理,探究其作为酸预处理试剂对甘蔗渣成分和酶解的影响。氨基磺酸预处理最优条件为浓度3%,温度121℃,预处理1 h。在该条件下,甘蔗渣的固体回收率为64.45%,半纤维素和木质素去除率分别为70.81%和25.10%,纤维素损失率仅7.56%。与硫酸、盐酸预处理相比,氨基磺酸的半纤维素和木质素去除率不如硫酸、盐酸预处理,但固体回收率更高,纤维素损失率低,能保留更多纤维素有效成分。进一步酶解显示,氨基磺酸预处理的纤维素转化率高于硫酸、盐酸预处理。氨基磺酸作为一种新的酸预处理试剂,在木质纤维素降解上有良好应用前景。     

Biosugar Production from <Emphasis Type="Italic">Gracilaria verrucosa</Emphasis> with Sulfamic Acid Pretreatment and Subsequent Enzymatic Hydrolysis

In this study, sulfamic acid-catalyzed pretreatment and subsequent enzymatic hydrolysis was conducted to produce biosugar from the marine macro-alga Gracilaria verrucosa. Sulfamic acid has dual active sites and is a green catalyst. Optimized sulfamic acid pretreatment at 130°C with 7.5% biomass and 100 mM sulfamic acid for 90 min yielded 39.9% total reducing sugar (TRS). Subsequent enzymatic hydrolysis yielded 69.1% TRS. These results indicate the potential of sulfamic acidcatalyzed pretreatment and subsequent enzymatic hydrolysis in producing biosugars using a biorefinery process.     

Synthesis and Study of Biological Activity of Sulfamic Polysaccharide Derivatives

New water-soluble derivatives of starch, pectin, and Na-CMC containing the sulfamic groups have been obtained by the reaction of sulfamic acid with dialdehyde polysaccharide derivatives. The structure and composition of the resulting compounds have been studied by IR spectroscopy, elemental (nitrogen and sulfur) analysis, and X-ray diffraction. The sulfamic derivatives of starch, pectin, and Na-CMC with a different content of the sulfamic groups have been obtained by varying the ratio of sulfamic acid to the dialdehyde polysaccharide derivatives. The optimal–СНО: NH₂SO₃H ratio was found to be 1: 2.5. The interaction rate of sulfamic acid with the dialdehyde derivatives of starch, pectin, and Na-CMC has been evaluated. The antibacterial and antifungal effects of sodium salts of the sulfamic starch, pectin, and Na-CMC derivatives against Gram-positive and Gram-negative bacteria and fungi have been studied at different concentrations (10, 25, 50 mg/mL) by the disk diffusion method. The synthesized compounds have not been found to exhibit antifungal activity against Candida albicans. Nevertheless, they have been shown to have the antibacterial activity against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Proteus vulgaris, Streptococcus faecalis, Streptococcus pyogenes, and Streptococcus faecalis at the concentration of 50 mg/mL. The concentration dependence of antibacterial action of sodium salts of the starch, pectin, and Na-CMC sulfamic derivatives has been demonstrated. The antibacterial activity of the drugs has been found to directly depend on the content of the sulfamic groups in polysaccharides. The results on the acute toxicity of the sulfamic polysaccharide derivatives have shown that these compounds can be attributed to low-toxicity substances of Class V.     

Design and synthesis of potent, non-peptidic inhibitors of HPTPbeta

The sulfamic acid phosphotyrosine mimetic was coupled with a previously known malonate template to obtain highly selective and potent inhibitors of HPTPbeta. Potentially hydrolyzable malonate ester functionalities were replaced with 1,2,4-oxadiazoles without a significant effect on HPTPbeta potency.     

Sulfation of Xylan with Sulfamic Acid in N,N-Dimethylformamide

Russian Journal of Bioorganic Chemistry - Sulfation of birch wood xylan by sulfamic acid in N,N-dimethylformamide (DMF) in the presence of urea was studied for the first time. The effect of the...     

Regioselective synthesis of 6-aryl-benzo[h][1,2,4]-triazolo[5,1-b]quinazoline-7,8-diones as potent antitumoral agents

Three-component coupling of aldehyde, 2-hydroxy-1,4-naphthoquinone and 3-amino-1,2,4-triazole has been achieved using a catalytic amount of sulfamic acid under solvent free conditions to produce a novel series of 6-aryl-benzo[h][1,2,4]-triazolo[5,1-b]quinazoline-7,8-dione derivatives in good yields and with high regioselectivity. These compounds are found to exhibit potent antitumoral properties.     

Carbonic anhydrase inhibitors: inhibition of isozymes I, II and IV by sulfamide and sulfamic acid derivatives

Sulfamide and sulfamic acid are the simplest compounds containing the SO2NH2 moiety, responsible for binding to the Zn(II) ion within carbonic anhydrase (CA, EC 4.2.1.1) active site, and thus acting as inhibitors of the many CA isozymes presently known. Here we describe two novel classes of CA inhibitors obtained by derivatizations of the lead molecules mentioned above. The new compounds, possessing the general formula RSO2NH-SO2X (X = OH, NH2), were obtained by reaction of sulfamide or sulfamic acid with alkyl/arylsulfonyl halides or arylsulfonyl isocyanates. A smaller series of derivatives has been obtained by reaction of aromatic aldehydes with sulfamide, leading to Schiff bases of the type ArCH = NSO2NH2. All the new compounds act as strong inhibitors of isozymes I, II and IV of carbonic anhydrase. Their mechanism of CA inhibition is also discussed based on electronic spectroscopic measurements on adducts with the Co(II)-substituted enzyme. These experiments led to the conclusion that the new inhibitors are directly coordinated (in a monodentate manner) to the metal ion within the enzyme active site, similarly to the classical inhibitors, the aromatic/heterocyclic sulfonamides.     

Synthesis of N4-substituted CTP by mammalian CTP synthetase

Highly purified CTP synthetase from Ehrlich ascites tumor cells catalyzes the formation of N4-substituted CTP from UTP and hydroxylamine and its derivatives. The products with hydroxylamine and O-methylhydroxylamine were identified as N4-hydroxyCTP and N4-methoxyCTP by absorption spectra and chromatographic behavior on Dowex column, respectively. The weak nucleophilic amines such as methylamine, ethylamine or diethylamine and a less nucleophilic amine, sulfamic acid, did not react with UTP. These results suggest that the nucleophilicity and basicity of amines are important in the enzymic reaction with UTP.     

Carbonic anhydrase inhibitors. Inhibition of the prokariotic beta and gamma-class enzymes from Archaea with sulfonamides

A detailed inhibition study of carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the beta- and gamma-families from Archaea with sulfonamides has been performed. Compounds included in this study were the clinically used sulfonamide CA inhibitors, such as acetazolamide, methazolamide, ethoxzolamide, topiramate, valdecoxib, celecoxib, dorzolamide, sulfanilamide, dichlorophanamide, as well as sulfanilamide analogs, halogenated sulfanilamides, and some 1,3-benzenedisulfonamide derivatives. The two gamma-CAs from Methanosarcina thermophila (Zn-Cam and Co-Cam) showed very different inhibitory properties with these compounds, as compared to the alpha-CA isozymes hCA I, II, and IX, and the beta-CA from Methanobacterium thermoautotrophicum (Cab). The best Zn-Cam inhibitors were sulfamic acid and acetazolamide, with inhibition constants in the range of 63-96 nM, whereas other investigated aromatic/heterocylic sulfonamides showed a rather levelled behavior, with KIs in the range of 0.12-1.70 microM. The best Co-Cam inhibitors were topiramate and p-aminoethyl-benzenesulfonamide, with KIs in the range of 0.12-0.13 microM, whereas the worst one was homosulfanilamide (KI of 8.50 microM). In the case of Cab, the inhibitory power of these compounds varied to a much larger extent, with sulfamic acid and sulfamide showing millimolar affinities (KIs in the range of 44-103 mM), whereas the best inhibitor was ethoxzolamide, with a KI of 5.35 microM. Most of these sulfonamides showed inhibition constants in the range of 12-100 microM against Cab. Thus, the three CA families investigated up to now possess a very diverse affinity for sulfonamides, the inhibitors with important medicinal, and environmental applications.     

Anodic alumina films formed in sulfamic acid solution

The formation of anodic oxide films on aluminium in 5% aqueous solution of sulfamic acid is investigated. The investigations were carried out in galvanostatic conditions and at different temperatures and durations. The porosity of porous alumina samples grown under different conditions is determined by the pore-filling method and scanning electron microscopy. The effect of the current density, temperature and duration of the anodic oxidation on the morphology of the porous Al₂O₃-films is studied.     

Silica-bonded N-propyl sulfamic acid used as a heterogeneous catalyst for transesterification of soybean oil with methanol

The transesterification of soybean oil with methanol was carried out, to produce biodiesel, over silica-bonded N-propyl sulfamic acid in a heterogeneous manner. Results showed that a maximum conversion of 90.5% was achieved using a 1:20 M ratio of soybean oil to methanol and a catalyst amount of 7.5 wt.% at 423 K for 60 h. It was found that the free fatty acid (FFA) and water present in the feedstock had no significant influence on the catalytic activity to the transesterification reaction. Besides, the catalyst also showed activities towards the esterification reaction of FFAs, in terms of the FFA conversion of 95.6% at 423 K for 30 h. Furthermore, the catalyst could be recovered with a better reusability.     

Carbonic Anhydrase Inhibitors: Inhibition of Isozymes I,II and IV by Sulfamide and Sulfamic Acid Derivatives

Abstract

Sulfamide and sulfamic acid are the simplest compounds containing the SO₂NH₂ moiety, responsible for binding to the Zn(II) ion within carbonic anhydrase (CA, EC 4.2.1.1) active site, and thus acting as inhibitors of the many CA isozymes presently known. Here we describe two novel classes of CA inhibitors obtained by derivatizations of the lead molecules mentioned above. The new compounds, possessing the general formula RSO₂NH-SO₂X (X = OH, NH₂), were obtained by reaction of sulfamide or sulfamic acid with alkyl/arylsulfonyl halides or aryl-sulfonyl isocyanates. A smaller series of derivatives has been obtained by reaction of aromatic aldehydes with sulfamide, leading to Schiff bases of the type ArCH=NSO₂NH₂. All the new compounds act as strong inhibitors of isozymes I, II and IV of carbonic anhydrase. Their mechanism of CA inhibition is also discussed based on electronic spectroscopic measurements on adducts with the Co(II)-substituted enzyme. These experiments led to the conclusion that the new inhibitors are directly coordinated (in a monodentate manner) to the metal ion within the enzyme active site, similarly to the classical inhibitors, the aromatic/heterocyclic sulfonamides.     

A Revised Iron Extraction Protocol for Environmental Samples Rich in Nitrite and Carbonate

Wet-chemical iron extraction is widely applied to quantify the mineral-bound ferriferous fraction of sediments and soils. As previously shown, this method is strongly affected by the composition of the soil/sediment. Samples enriched in mostly microbially produced nitrite require the removal of the nitrite-containing aqueous phase or the replacement of HCl with sulfamic acid (SA) as the extractant. In this study, we show that sedimentary carbonate buffers SA, inhibiting the stabilization of Fe(II) and effective extraction of iron. We therefore provide a revised extraction protocol which allows the preservation of low pH conditions, leading to efficient iron extraction in nitrite- and carbonate-enriched samples.     

Carbonic anhydrase inhibitors. Inhibition studies with anions and sulfonamides of a new cytosolic enzyme from the scleractinian coral Stylophora pistillata

The catalytic activity and the inhibition of a new coral carbonic anhydrase (CA, EC 4.2.1.1), from the scleractinian coral Stylophora pistillata, STPCA-2, has been investigated. STPCA-2 has high catalytic activity for the physiological reaction being less sensitive to anion and sulfonamide inhibitors compared to STPCA, a coral enzyme previously described. The best STPCA-2 anion inhibitors were sulfamide, sulfamic acid, phenylboronic acid, and phenylarsonic acid (K_Is of 5.7-67.2 μM) whereas the best sulfonamide inhibitors were acetazolamide and dichlorophenamide (K_Is of 74-79 nM). Because this discriminatory effect between these two coral CAs, sulfonamides may be useful to better understand the physiological role of STPCA and STPCA-2 in corals and biomineralization processes.     

Anion inhibition studies of the α-carbonic anhydrase from the protozoan pathogen Trypanosoma cruzi,the causative agent of Chagas disease

The protozoan pathogen Trypanosoma cruzi, the causative agent of Chagas disease, encodes an α-class carbonic anhydrase (CA, EC 4.2.1.1), TcCA, which was recently shown to be crucial for its life cycle. Thiols, a class of strong TcCA inhibitors, were also shown to block the growth of the pathogen in vitro. Here we report the inhibition of TcCA by inorganic and complex anions and other molecules interacting with zinc proteins, such as sulfamide, sulfamic acid, phenylboronic/arsonic acids. TcCA was inhibited in the low micromolar range by iodide, cyanate, thiocyanate, hydrogensulfide and trithiocarbonate (K_Is in the range of 44–93 μM), but the best inhibitor was diethyldithiocarbamate (K_I = 5 μM). Sulfamide showed an inhibition constant of 120 μM, but sulfamic acid was much less effective (K_I of 10.6 mM). The discovery of diethyldithiocarbamate as a low micromolar TcCA inhibitor may be useful to detect leads for developing anti-Trypanosoma agents with a diverse mechanism of action compared to clinically used drugs (benznidazole, nifurtimox) for which significant resistance emerged.     

Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate‐reducing Fe(II) oxidizer Acidovorax sp. BoFeN1 – questioning the existence of enzymatic Fe(II) oxidation

Nitrate‐reducing, Fe(II)‐oxidizing bacteria were suggested to couple with enzymatic Fe(II) oxidation to nitrate reduction. Denitrification proceeds via intermediates (, NO) that can oxidize Fe(II) abiotically at neutral and particularly at acidic pH. Here, we present a revised Fe(II) quantification protocol preventing artifacts during acidic Fe extraction and evaluate the contribution of abiotic vs. enzymatic Fe(II) oxidation in cultures of the nitrate‐reducing, Fe(II) oxidizer Acidovorax sp. BoFeN1. Sulfamic acid used instead of HCl reacts with nitrite and prevents abiotic Fe(II) oxidation during Fe extraction. Abiotic experiments without sulfamic acid showed that acidification of oxic Fe(II) nitrite samples leads to 5.6‐fold more Fe(II) oxidation than in anoxic samples because the formed NO becomes rapidly reoxidized by O₂, therefore leading to abiotic oxidation and underestimation of Fe(II). With our revised protocol using sulfamic acid, we quantified oxidation of approximately 7 mm of Fe(II) by BoFeN1 within 4 days. Without addition of sulfamic acid, the same oxidation was detected within only 2 days. Additionally, abiotic incubation of Fe(II) with nitrite in the presence of goethite as surface catalyst led to similar abiotic Fe(II) oxidation rates as observed in growing BoFeN1 cultures. BoFeN1 growth was observed on acetate with N₂O as electron acceptor. When adding Fe(II), no Fe(II) oxidation was observed, suggesting that the absence of reactive N intermediates (, NO) precludes Fe(II) oxidation. The addition of ferrihydrite [Fe(OH)₃] to acetate/nitrate BoFeN1 cultures led to growth stimulation equivalent to previously described effects on growth by adding Fe(II). This suggests that elevated iron concentrations might provide a nutritional effect rather than energy‐yielding Fe(II) oxidation. Our findings therefore suggest that although enzymatic Fe(II) oxidation by denitrifiers cannot be fully ruled out, its contribution to the observed Fe(II) oxidation in microbial cultures is probably lower than previously suggested and has to be questioned in general until the enzymatic machinery‐mediating Fe(II) oxidation is identified.     

Inhibitory effects of sulfamic acid on three thiosulfate-oxidizing chemolithotrophs

Sulfamate is an analogue of thiosulfate, and the sodium and potassium salts of sulfamic acid inhibited the chemolithoautotrophic growth on thiosulfate of Acidithiobacillus ferrooxidans and Halothiobacillus neapolitanus. The chemo-organotrophic growth of Paracoccus versutus on sucrose was similarly inhibited by sulfamate. Thiosulfate oxidation by suspensions of H. neapolitanus was, however, unaffected by sulfamate, showing that sulfamate did not directly affect thiosulfate uptake, activation or oxidation. Inhibition of P. versutus was not relieved by cysteine and methionine, indicating that sulfate uptake and sulfur amino acid biosynthesis were not directly affected by sulfamate. Sulfamate was not degraded by any of the bacteria, and so could not serve as an alternative to thiosulfate as an energy-yielding substrate. Sulfamate is also an analogue of ammonia and might act like hydrazine by inhibiting ammonium uptake or an essential enzyme activity.     

Cholecalciferol sulfate identification in human milk by HPLC

Synthetic vitamin D3 sulfate was prepared by reacting cholecalciferol with sulfamic acid in pyridine. Vitamin D3 sulfate ammonium salt was purified by crystallisation and transformed in sulfate sodium salt. Homogeneity was controlled by reverse phase high pressure liquid chromatography (HPLC). Purified synthetic vitamin D3 sulfate sodium salt was used as a reference. Milk whey was obtained after protein precipitation by adding ethanol. Vitamin D3 sulfoconjugate was identified in supernatant (lyophylized) after purification by Sephadex LH 20 and HPLC. Milk whey purified fraction obtained exhibited the same ultra-violet absorption (UV) as synthetic vitamin D3 sulfate; after solvolysis, cholecalciferol was liberated from natural and synthetic sulfoconjugate. The results confirmed that vitamin D3 sulfate was present in human milk.     

Anion inhibition studies of an α-carbonic anhydrase from the living fossil Astrosclera willeyana

An α-carbonic anhydrase (CA, EC 4.2.1.1) isolated from the living fossil sponge Astrosclera willeyana, Astrosclerin, was investigated for its inhibition profile with simple inorganic anions, complex anions and other small molecules known to interact with these zinc enzymes. Astrosclerin is a catalytically highly efficient enzyme, and is inhibited in the low micromolar range by sulfamide, sulfamic acid, phenylboronic acid and phenylarsonic acid, and in the submillimolar range by a variety of anions including fluoride, chloride, cyanate, thiocyanate, cyanide, hydrogen sulfide, bisulfate, stannate, perosmate, divanadate, perrhenate, perruthenate, selenocyanide, trithiocarbonate, diethyldithiocarbamate and iminodisulfonate. Less efficient Astrosclerin inhibitors were sulfate, bromide, iodide, azide, bicarbonate, carbonate, tetraborate and perchlorate (K(I)s of 5.11-30.6mM) whereas tetrafluoroborate was not at all inhibitory. Because Astrosclerin is involved in calcification processes in vivo, its anion inhibition profile may be important for future studies designed to shed light on the physiologic functions of α-CAs in marine organisms.     

Studies on the bioluminescence of Renilla reniformis. XI. Location of the sulfate group in luciferyl sulfate

1. Luciferin, in the coelenterate Renilla reniformis, is stored as a sulfate derivative which we have termed luciferyl sulfate. The chemical behavior of luciferyl sulfate, and its absorption characteristics in the infrared, suggest that the sulfate moiety is attached to luciferin via an acid sulfate linkage equivalent to that of ascorbic acid sulfate. This has been confirmed by the chemical synthesis of luciferyl sulfate from luciferin and sulfamic acid. The properties of the synthetic compound are identical to those of the natural one. In both cases luciferin sulfokinase and 3′,5′-diphosphoadenosine are required for light production, in addition to luciferase and O₂, and the kinetics of light emission are identical.

2. A simplified procedure for the isolation of luciferyl sulfate is also given which results in the extraction of essentially all of this compound from Renilla. This procedure has been used to isolate Renilla-like luciferyl sulfates from other coelenterates such as Cavernularia, suggesting that the method has general application.