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PubMed2003

Response of the zooplankton community and environmental fate of perfluorooctane sulfonic acid in aquatic microcosms.

Little is known regarding perfluorooctane sulfonic acid (PFOS) toxicity to freshwater organisms. This field evaluation aims to assess the toxicological risk associated with exposure to PFOS across levels of biological organization. The analysis of variance study was conducted in replicate (n = 3) 12,000 L outdoor microcosms. Multivariate techniques were used to assess the response of zooplankton community structure and dynamics, as well as a floating macrophyte, Lemna gibba. The zooplankton community was significantly affected (p < 0.05) by the treatment regime given by the Monte Carlo permutations for all sampling times. A community-level no-observable-effect concentration ([NOEC]community) of 3.0 mg/L was determined for the 35-day study, however, longer term studies are recommended. The most sensitive taxonomic groups, Cladocera and Copepoda, were virtually eliminated in 30 mg/L treatments after 7 d. The 42-d 50% inhibition concentration (IC50) for L. gibba frond number was 19.1 mg/L and the NOEC was 0.2 mg/L. Furthermore, we investigated the persistence of PFOS over 285 d in microcosms under natural conditions. Perfluorooctane sulfonic acid concentration showed no drastic reduction in any treatment microcosm over the entire study period, confirming that this compound undergoes little degradation in aquatic systems. Presently, there appears to be little hazard to these freshwater organisms at reported environmental concentrations.

Alkanesulfonic Acids↗
PubMed2003

Crystal structure of zwitterionic trimethylammoniopropane sulfonate.

Crystal structure of zwitterionic trimethylammoniopropane sulfonate (Z1-Methyl) was determined by single-crystal X-ray diffractometry. Z1-Methyl crystallized in the monoclinic system, space group P2(1), with a = 6.3639(2), b = 10.9237(4), c = 8.1505(4) A, beta = 111.078(2) degrees, V = 528.69(4) A3, Z = 2. An inter-molecular ionic association was observed in the crystal. The shortest distance between the methyl protons of the trimethylammonium group and the oxygens of the sulfonate group was 2.51(2) A.

Journal Article↗
PubMed2004

Exisulind: Aptosyn, FGN 1, Prevatac, sulindac sulfone.

Exisulind [Aptosyn trade mark, FGN 1 trade mark, Prevatac trade mark, sulindac sulfone], the sulfone derivative of sulindac, is the lead compound in a series of selective apoptotic antineoplastic drugs (SAANDs) being developed by OSI Pharmaceuticals. The compounds were originally developed by Cell Pathways, which was acquired by, and integrated into, OSI Pharmaceuticals in June 2003. Exisulind inhibits the enzyme cyclic GMP phosphodiesterase (GMP-PDE), overexpressed in precancerous and cancerous colorectal cells, and induces apoptosis in such cells with minimal effects on normal cells. This apoptotic effect is independent of COX I or COX II inhibition, p53, Bcl-2, or cell-cycle arrest. Preclinical evidence suggests that exisulind also inhibits angiogenesis. Cell Pathways has formed sales and distribution agreements with three healthcare-related companies in the US for its future marketing and support campaign for exisulind. Innovex will hire and train sales representatives for Cell Pathways to launch and promote exisulind, Livingston Healthcare Services will be responsible for customer service, order and distribution administration, and Lash Group will be responsible for the development and implementation of reimbursement support services for exisulind. Cell Pathways has issued an exclusive licence for exisulind to Paladin Labs of Montreal, Canada. The agreement allows Paladin exclusive rights to commercialise the drug in Canada. In August 1999 Cell Pathways submitted an NDA application to the US FDA for exisulind (Aptosyn) for the treatment of familial adenomatous polyposis (FAP). However, in September 2000, the FDA announced that it had found deficiencies in the safety and efficacy data of Cell Pathways' NDA, and returned a non-approvable letter to the company. Cell Pathways then initiated another phase III study of the agent in combination with Aventis' docetaxel and comparing combination therapy with docetaxel alone. Exisulind has fast-track designation for FAP in the US. Phase I and II paediatric trials are also underway in the US. Cell Pathways announced in April 2000 that it had completed enrollment in an open-label phase II study in children with familial adenomatous polyposis (FAP). Patients will be evaluated to determine whether polyp numbers have been reduced after 1 year relative to baseline. In June 2000, Cell Pathways announced the results of a 1-year extension of a 1997-1999 phase III trial that showed that exisulind significantly reduced polyp formation in patients with FAP. Enrollment of 282 patients in a multicentre, placebo-controlled phase III trial for the treatment of sporadic colonic polyps was completed in the US in May 1999. In its 2003 Annual Report, Paladin Labs announced that it is conducting a phase III study of exisulind in patients with prostate cancer in Canada. Exisulind has completed a pivotal phase II/III trial for preventing the recurrence of prostate cancer in the US. Two phase II prostate cancer trials were initiated in June 1999. The first study assessed the efficacy of exisulind in 15 patients who had undergone prostatectomy, were receiving LHRH-agonist hormone therapy and had increasing PSA levels (study EX1001). The second trial was to enroll 20 hormone-refractory patients scheduled for radical prostatectomy within 2-8 weeks of diagnosis (study EX1004). This study compared the effect of exisulind + docetaxel on the rate of apoptosis and GMP-PDE expression in premalignant or malignant and normal prostate tissue. Cell Pathways and Rhône-Poulenc Rorer (now Aventis) agreed to collaborate on clinical trials of exisulind in combination with docetaxel in the treatment of various solid tumours. The first phase I/II trial (study 026) was to enroll previously untreated patients with non-small cell lung cancer (NSCLC). OSI Pharmaceuticals and Bristol-Myers Squibb are conducting a phase I/II trial (study EX 2002) of exisulind in combination with paclitaxel and carboplatin as first-line treatment for patients with NSCLC. Both companies will share costs and information gathered from the SCLC. Both companies will share costs and information gathered from the trial. A phase I/II trial (study EX 2006) of weekly paclitaxel and carboplatin combined with exisulind is also underway in patients with advanced NSCLC. Cell Pathways and Glaxo Wellcome are cooperating in supporting a clinical trial (study EX 2004) of exisulind in combination with vinorelbine as first-line treatment for elderly patients with advanced NSCLC. The study will be conducted at the University of Wisconsin, and the two companies will share the costs of the trial while maintaining the rights to their respective compounds. Cell Pathways and Eli Lilly have a phase I/II trial (study EX 2005) of exisulind in combination with gemcitabine underway in patients with NSCLC. This study will investigate the efficacy and tolerability of escalating doses of exisulind in combination with a standard gemcitabine regimen. The Cancer and Leukaemia Group B (CALGB) initiated a phase II study of exisulind in combination with etoposide and carboplatin in patients with small cell lung cancer in the US in September 2002. The Eastern Cooperative Oncology Group (ECOG) initiated a phase II study in NSCLC patients in September 2002 that will investigate the effects of exisulind in combination with gemcitabine and carboplatin. The objectives of the two studies are to determine the 12-month survival rate and response rates following treatment with the combination regimens. Patents covering the mechanism of action of exisulind have been allowed in Europe and Japan, and extend to the methods of identifying compounds that selectively stimulate apoptosis in precancerous and cancerous cells.

Animals↗
PubMed1979

Anion transport in red blood cells. I. Chemical properties of anion recognition sites as revealed by structure-activity relationships of aromatic sulfonic acids.

The present study is concerned with the chemical factors that determine the inhibitory properties of reversible aromatic sulfonic acids on sulfate exchange system of human red blood cells. Two series of compounds were tested for inhibitory potencies: benzene sulfonic acid (BS) and 2,2'-disulfonic stilbene (DS) derivatives, each series with substituent groups such as Cl, OH, NH2, NO2, NNN, N-acetamido, and N-benzoamido. As judged by various kinetic criteria, all congeners of BS and DS appear to have common sites of action in the anion transport system. The range of inhibitory potencies, as defined by the concentration required to produce 50% inhibition (ID50), varied over a 10(4) range (ID50:2-50,000 microM). The degree of inhibition was correlated with two physicochemical properties of the substituent groups: (a) lipophilicity, as judged by the pi values (Hansch factor) of the groups; and (b) the electronic character, as judged by sigma values (Hammett factor) of the groups. Optimal correlations were obtained with a linear combination of the two factors. Based on the above structure-activity relationships and on a comparison between the inhibitory properties of congeners of BS and DS, we suggest that the microenvironment of substrate recognition sites bears a positive multipolar character and possesses functionally essential groups with electron donor capacity embedded in a hydrophobic area.

Anions↗
PubMed1979

Anion transport in red blood cells. II. Kinetics of reversible inhibition by nitroaromatic sulfonic acids.

The anion exchange system of human red blood cells is highly inhibited and specifically labeled by isothiocyano derivatives of benzene sulfonate (BS) or stilbene disulfonate (DS). To learn about the site of action of these irreversibly binding probes we studied the mechanism of inhibition of anion exchange by the reversibly binding analogs p-nitrobenzene sulfonic acid (pNBS) and 4,4'-dinitrostilbene-disulfonic acid (DNDS). In the absence of inhibitor, the self-exchange flux of sulfate (pH 7.4, 25 degrees C) at high substrate concentration displayed self-inhibitory properties, indicating the existence of two anion binding sites: one a high-affinity transport site and the other a low-affinity modifier site whose occupancy by anions results in a noncompetitive inhibition of transport. The maximal sulfate exchange flux per unit area was JA = (0.69 +/- 0.11) X 10(-10) moles . min-1 . cm-2 and the Michaelis-Menten constants were for the transport site KS = 41 +/- 14 mM and for the modifier site Ks' = 653 +/- 242 mM. The addition to cells of either pNBS at millimolar concentrations or DNDS at micromolar concentrations led to reversible inhibition of sulfate exchange (pH 7.4, 25 degrees C). The relationship between inhibitor concentration and fractional inhibition was linear over the full range of pNBS or DNDS concentrations (Hill coefficient n approximately equal to 1), indicating a single site of inhibition for the two probes. The kinetics of sulfate exchange in the presence of either inhibitor was compatible with that of competitive inhibition. Using various analytical techniques it was possible to determine that the sulfate transport site was the target for the action of the inhibitors. The inhibitory constants (Ki) for the transport sites were 0.45 +/- 0.10 microM for DNDS and 0.21 +/- 0.07 mM for pNBS. From the similarities between reversibly and irreversibly binding BS and DS inhibitors in structures, chemical properties, modus operandi, stoichiometry of interaction with inhibitory sites, and relative inhibitory potencies, we concluded that the anion transport sites are also the sites of inhibition and of labeling of covalent binding analogs of BS and DS.

Anions↗
PubMed2005

Effects of Changtai granules, a traditional compound Chinese medicine, on chronic trinitrobenzene sulfonic acid-induced colitis in rats.

AIM: To study the effects of Changtai granules (CTG), a traditional compound Chinese medicine, on chronic trinitrobenzene sulfonic acid-induced colitis in rats. METHODS: Healthy adult Sprague-Dawley (SD) rats of both sexes, weighing 250-300 g, were employed in the present study. The rat colitis models were induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) enemas at a concentration of 100 mg/kg in 50% ethanol. The experimental animals were randomly divided into dexamethasone (DX) treatment, CTG treatment, and model control groups, which were intracolicly treated daily with DX (0.2 mg/kg), CTG at doses of 2.9, 5.7 and 11.4 g crude drug/kg, and the equal amount of saline respectively from 6 h following induction of the colitis in rats inflicted with TNBS to the end of study. A normal control group of rats treated without TNBS but saline enema was also included in the study. After 3 wk of treatment, the animals were assessed for colonal inflammatory and ulcerative responses with respect to mortality, frequency of diarrhea, histology and myeloperoxidase activity (MPO). RESULTS: The therapeutic effect of CTG on ulcerative colitis (UC) was better than DX. CTG effectively inhibited the activity of granulocytes, macrophages and monocytes in a dose-dependent manner. Also it reduced MPO and formation of inflammation in colonic mucosal tissue. Furthermore, administration of CTG significantly prevented body mass loss and death, and decreased frequency of diarrhea in UC rats, when compared with the model control group rats. CONCLUSION: CTG would prove to be an ideal drug for chronic UC, and is warranted to be studied further.

Animals↗
PubMed1985

Chemical modification of sulfazecin. Synthesis of 4-(substituted methyl)-2-azetidinone-1-sulfonic acid derivatives.

In expectation of improving the antibacterial activity of sulfazecin by chemical modification at the 3- and 4-positions, a number of 3-[2-(2-aminothiazol-4-yl)-(Z)-2-(substituted oxyimino)-acetamido]-4-(substituted methyl)-2-azetidinone-1-sulfonic acids were synthesized. Among various 4-substituents explored, the carbamoyloxymethyl group was found to provide a good effect to the antibacterial activity of these 2-azetidinone derivatives. An extensive study of structure-activity relationships led to selecting (3S,4S)-3-[2-(2-aminothiazol-4-yl)-(Z)-2-carboxymethoxyiminoace tamido]-4- carbamoyloxymethyl-2-azetidinone-1-sulfonic acid, AMA-1080 (Ro 17-2301), which has highly potent antibacterial activity against Gram-negative bacteria including Pseudomonas aeruginosa, for further biological and subsequent clinical evaluation.

Anti-Bacterial Agents↗
PubMedDate not supplied

Evaluation of poly(styrene-4-sulfonate) as a preventive agent for conception and sexually transmitted diseases.

A commercial preparation of a sodium polystyrene sulfonate (designated as N-PSS; its molecular weight is 500000 daltons) was tested as an inhibitor of sperm function and as a preventive agent for conception and the transmission of sexually transmitted diseases. The polymer is an irreversible inhibitor of hyaluronidase and acrosin; its IC50 values are 5.7 microg/mL and 0.5 microg/mL, for hyaluronidase and acrosin, respectively. N-PSS is also a stimulus of human sperm acrosomal loss. It produces maximal acrosomal loss at 2.5 microg/mL. Contraception in rabbits is nearly complete when rabbit spermatozoa are pretreated with 0.5 mg/mL of N-PSS before artificial insemination; however, N-PSS does not immobilize spermatozoa at concentrations as high as 50 mg/mL. N-PSS has broad spectrum antiviral and antibacterial activities. Infection by human immunodeficiency virus and herpes simplex virus are inhibited by N-PSS; 3-log reductions are produced by 7 microg/mL and 3 microg/mL, respectively. N-PSS is active against Chlamydia trachomatis and Neisseria gonorrhoeae. At 1 mg/mL, N-PSS inhibits chlamydial infectivity by more than 90%. N-PSS produces a 3-log reduction in gonococcal growth at 15 microg/mL. In contrast, N-PSS (5 mg/mL) does not affect the growth of Lactobacillus (normal component of the vaginal flora). N-PSS can be classified as a noncytotoxic contraceptive antimicrobial agent. These properties justify bringing a polystyrene sulfonate into clinical trials for its evaluation as a preventive agent for conception and several sexually transmitted diseases.

Animals↗
PubMed1975

On the properties of solid and liquid ion exchangers. II. Infrared and NMR studies of lithium and cesium salts of dinonylnaphtalene sulfonic acid in heptane.

Infrared and NMR measurements on solutions of lithium and cesium dinonylnaphtalene sulfonates (DNNS-salts) in heptane show that the state of water in these systems is in several respects similar to its state in solid ion exchange resins and in some respects also similar to that in ordinary water. The two cations differ in their interaction with the sulfonic acid group at low water contents, the interaction being stronger for Li+. Spin-lattice relaxation measurements on LiDNNS show that the state of lithium both in DNNS and in solid resins is quite different from that of lithium salts in aqueous solutions of the corresponding concentration.

Chromatography, High Pressure Liquid↗
PubMed2003

Anaerobic degradation of linear alkylbenzene sulfonate.

Linear alkylbenzene sulfonate (LAS) found in wastewater is removed in the wastewater treatment facilities by sorption and aerobic biodegradation. The anaerobic digestion of sewage sludge has not been shown to contribute to the removal. The concentration of LAS based on dry matter typically increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C12 LAS), which show that C12 LAS was biodegradable under methanogenic conditions. Sorption of C12 LAS on sewage sludge was described with a Freundlich isotherm. The C12 LAS sorption was determined with different concentrations of total solids (TS). In the semi-continuously stirred tank reactor, 18% of the added C12 LAS was bioavailable and 20% was biotransformed when spiking with 100 mg/L of C12 LAS and a TS concentration of 14.2 mg/L. Enhanced bioavailability of C12 LAS was obtained in an upflow anaerobic sludge blanket (UASB) reactor inoculated with granular sludge and sewage sludge. Biodegradation under thermophilic conditions was 37% with LAS as sole carbon source. Benzaldehyde was produced in the UASB reactor during LAS transformation.

Alkanesulfonic Acids↗
PubMed2002

Polyurethane and sulfonated polysulfone blend ultrafiltration membranes. I. Preparation and characterization studies.

Polyurethane (ether type) and sulfonated polysulfone (sodium salt form) in the presence of polyethylene glycol 600 were blended in various compositions using N,N'-dimethylformamide as solvent and used for preparing ultrafiltration membranes by the phase inversion technique. Polymer blend composition, additive concentration, and casting and gelation conditions were optimized. Blend membranes were subjected to ultrafiltration characterizations such as compaction, pure water flux, water content, and membrane resistance. The membranes were also subjected to the determination of pore statistics and molecular weight cutoff determination studies using dextran of different molecular weights. Surface morphology of the membranes was analyzed using scanning electron microscopy at different magnifications. The effects of polymer composition and additive concentration on the above parameters were analyzed and the results are compared and discussed with those of pure sulfonated polysulfone membranes. The derived pore size, porosity, and number of pores have a remarkable interrelationship and also have a definite role and relationship with the molecular weight cutoff, morphology, and flux performance of the membranes.

Journal Article↗
PubMed2004

In vitro evaluation of dimethane sulfonate analogues with potential alkylating activity and selective renal cell carcinoma cytotoxicity.

We identified five structurally related dimethane sulfonates with putative selective cytotoxicity in renal cancer cell lines. These compounds have a hydrophobic moiety linked to a predicted alkylating group. A COMPARE analysis with the National Cancer Institute Anticancer Drug Screen standard agent database found significant correlations between the IC50 of the test compounds and the IC50 of alkylating agents (e.g., r = 0.68, P < 0.00001 for chlorambucil). In this report, we examined whether these compounds had activities similar to those of conventional alkylating agents. In cytotoxicity studies, chlorambucil-resistant Walker rat carcinoma cells were 4- to 11-fold cross-resistant to the test compounds compared with 14-fold resistant to chlorambucil. To determine effects on cell cycle progression, renal cell carcinoma (RCC) line 109 was labeled with bromodeoxyuridine prior to drug treatment. Complete cell cycle arrest occurred in cells treated with an IC90 dose of NSC 268965. p53 protein levels increased as much as 5.7-fold in RCC line 109 and as much as 20.4-fold in breast cancer line MCF-7 following an 18-hour drug exposure. Finally, DNA-protein cross-links were found following a 6-hour pretreatment with all compounds. Thus, the dimethane sulfonate analogues have properties expected of some alkylating agents but, unlike conventional alkylating agents, appear to possess activity against RCC.

Alkylating Agents↗
PubMed2003

Sulfonate ester hydroxamic acids as potent and selective inhibitors of TACE enzyme.

Sulfonamide hydroxamate derivatives of anthranilic acids are known to be potent inhibitors of cell-free TACE enzyme. However, compounds of this structural class with both high potency and high selectivity for TACE over matrix metalloproteinases (MMPs) are uncommon. Replacement of the sulfonamide functionality with an isosteric sulfonate ester has resulted in a series of sulfonate ester hydroxamates, 2a-e, with excellent activity against TACE and excellent selectivity over MMP-1 and MMP-13. Although compounds 2a-e possess good permeability in a PAMPA assay, they are only weakly active as inhibitors of lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF) production in human monocytic THP-1 cells. Protein binding affinity also does not predict the lack of cellular activity for these analogs.

ADAM Proteins↗
PubMed2005

[Experimental and clinical studies on the effect of sodium dodecylbenzene sulfonate in in vitro killing Demodex and in treating demodicidosis].

OBJECTIVE: To observe the effect of sodium dodecylbenzene sulfonate (SDBS) in killing Demodex in vitro and in the treatment of demodicidosis. METHODS: (1) The experiment of in vitro killing Demodex with 1% and 2% SDBS was conducted. (2) A clinical trial was carried out to evaluate the therapeutic effect in the treatment of demodicidosis with 2% SDBS and 2% metronidazole emulsion. Patients with demodicidosis were randomly divided into trial and control groups (31 cases each). They were treated with 2% SDBS ointment and 2% metronidazole ointment twice a day in the early morning and evening respectively for eight weeks consecutively. Inflammatory lesions of face, Demodex infestation and scores of erythema were measured to evaluate the effect before and after treatment. (3) Follow-up was carried out for two months to evaluate the effect and side effects after 8 weeks' treatment. RESULTS: (1) 2% SDBS killed all Demodex in vitro after 5 h, there was significant difference between the 2% SDBS and 2% metronidazole (69.4%), or between SDBS and peanut oil (9.1%) (P < 0.05). There was no significant difference in killing Demodex folliculorum and Demodex brevis with 2% SDBS. (2) Clinical observation showed that there was a significant difference in facial inflammatory lesions, Demodex infestation and scores of erythema before and after treatment with 2% SDBS (P < 0.05). The effective rate was 87.1%, 65.5% in 2% SDBS group and 2% metronidazole group respectively, with a significant difference between the two groups (P < 0.05). Follow up showed same results. (3) A slight burning sensation was the only side-effect in 3 cases with 2% SDBS ointment. CONCLUSION: Sodium dodecylbenzene sulfonate has the effect of in vitro killing Demodex and is highly effective in the treatment of demodicidosis.

Adolescent↗
PubMed1977

[Effect of methionine sulfone on the growth of Citrobacter intermedius C3 (author's transl)].

Specific activity of glutamate dehydrogenase (GD) and glutamate synthase (GtS) has been determined in the wild strain C3 and on a non excreting pro- mutant strain. Methionine sulfone shows inhibitory effects on their growth. The addition of alpha-ketoglutarate to the medium prevents the inhibitory effect and increases the GtS specific activity in both strains. The physiological effect of methionine sulfone and its suppression by alpha-ketoglutarate is discussed.

Animals↗
PubMed1987

[Clinical value of ethinyl estradiol sulfonate (Turisteron)--long-term results of a randomized compound study].

In a randomized compound study the therapy effect of ethinylestradiol sulfonate (Turisteron) is tested. As comparative groups serve patients with chemotherapy and Turisteron in combination with chemotherapy. The cumulative 5-year survival rate under the therapy of Turisteron was 61.2%. The comparative groups do not achieve this high survival rate. In connection with the slight stress of the patients (application form, side effects) ethinylestradiol sulfonate (Turisteron) is an effective estrogen in the long-term treatment of the advanced carcinoma of the prostate gland.

Aged↗
PubMed1989

[Bonding of MMA-BPO. DMPT resin to bovine tooth coated by poly (methyl methacrylate-co-p-styrene sulfonic acid)].

The objective of this study was to prepare a new type water-soluble bonding agent, methyl methacrylate (MMA)-p-styrene sulfonic acid copolymer (MS), and to investigate the effect of MS on bonding between resins and tooth substrates. MS is cross-linked with Ca2+ released from ground enamel and dentin and could be immobilized on their surface. A sample was prepared by bonding an acrylic rod with a BPO-amine catalyzed self-curing resin to ground enamel and dentin coated with an aqueous mixture of FeCl3 and 10 wt% MS. After immersion in water for 24 hrs, the tensile bond strength was measured. The bond strength to both enamel and dentin was only 2 MPa and adhesive failure occurred at the interface between cured MS and self-curing resin. This suggested that cured MS could adversely effect the polymerization of self-curing resins. A second treatment of cured MS on the tooth surface with metallic cations was carried out to minimize the amount of free sulfonic acids in the MS disturbing radical formation in self-curing resin. The second treatment improved the bond strength to 6 MPa.

Acrylic Resins↗
PubMed1989

H spin system identifications of S-sulfonated insulin B chain with 2D-NMR.

Resonance assignments of the 1H spectrum of insulin are the basis on which to investigate its solution conformation by using NMR method. Owing to the complicated aggregation behaviour of the molecule to give broadened n. m. r. lines, only limited resonance assignments have been reported. S-sulfonated A and B chains of insulin gave 1H spectra with good resolutions. Based on the 500 MHz absolute 2D-COSY spectrum and 400 MHz phase sensitive DQF-COSY, Relayed-COSY and NOESY spectra of B chain recorded in D2O, all of the spin system identifications of the non-labile protons in the S-sulfonated B chain of insulin were reported including the specific resonance assignments of eight residues: B3Asn, B9Ser, B16Tyr, B22Arg, B26Tyr, B27Thr, B28Pro and B29Lys. The pK values of B16 and B26 tyrosine are 10.65 and 10.60 respectively from pH titration.

Animals↗