Synthesis of a quaternary polyprenyl ammonium salt

Reaction of primary C(55)-allylic alcohol moraprenol (WT(3)C(7-9)-OH, a polyprenol from mulberry leaves) with triethylamine in the presence of phosphorus oxychloride leads to a quaternary ammonium chloride with a good yield (72%) and high cis-stereoselectivity of the terminal isoprene unit. Cationic polyprenyl derivatives may be useful for transfection and immunological studies.     

Synthesis of galactomannan sulfates

The experimental conditions for the sulfation of legume galactomannans were found, which allow for the obtainment of polysaccharides with a high degree of substitution. Sulfate esters of four galactomannans of different composition (galactose content, 16.4–47.5%) were synthesized using the SO₃-pyridine complex in dimethylformamide as a sulfating agent. The degree of substitution was as high as 1.4–1.8; it did not correlate with the content of galactose in the polysaccharides. It was found that the degree of sulfation depended on the reaction temperature in the range of 19–60°C.     

Synthesis of galactomannan sulfates

The experimental conditions for the sulfation of legume galactomannans were found, which allow for the obtainment of polysaccharides with a high degree of substitution. Sulfate esters of four galactomannans of different composition (galactose content, 16.4-47.5%) were synthesized using the SO3-pyridine complex in dimethylformamide as a sulfating agent. The degree of substitution was as high as 1.4-1.8; it did not correlate with the content of galactose in the polysaccharides. It was found that the degree of sulfation depended on the reaction temperature in the range of 19-60 degrees C.     

Synthesis of [19- 2H3]-analogs of dehydroepiandrosterone and pregnenolone and their sulfates

Deuterated analogs of pregnenolone and pregnenolone sulfate with three atoms of deuterium in position 19 were prepared. The synthetic approach was developed on derivatives of dehydroepiandrosterone, where initial intermediates were well characterized, and then applied to the pregnenolone series. Starting 19-hydroxy compounds were transformed into 3alpha,5-cycloderivatives to simplify the Jones oxidation into the corresponding 19-oic acids. After oxidation, rearrangement to 3-hydroxy-5-enes, and suitable protection, two deuterium atoms were introduced by lithium aluminum deuteride reduction. Mesylate exchange by iodide in the presence of zinc and deuterium oxide added third deuterium atom. Deprotection gave title analogs with about 93-95% content of d3-derivative, the rest was mainly not fully deuterated d2-analogue as followed from the mass spectra analysis. Thus, 3beta-hydroxy[19-2H3]androst-5-en-17-one was prepared in 14 steps from 19-hydroxy-17-oxoandrost-5-en-3beta-yl acetate in 8.9% yield, the analogous sequence in the pregnenolone series gave 3beta-hydroxy[19-2H3]pregn-5-en-20-one in 7.3% yield. Corresponding sulfates were prepared via pyridinium salts in 53 and 57% yields, respectively. Fully assigned NMR data of selected pregnenolone derivatives were given.     

Synthesis of 2-deoxy-2-fluoro analogs of polyprenyl beta-D-arabinofuranosyl phosphates

Described is the synthesis of polyprenyl 2-deoxy-2-fluoro-beta-D-arabinofuranosyl phosphate derivatives, including an analog of decaprenyl beta-D-arabinofuranosyl phosphate, the donor species used by the arabinosyltransferases involved in mycobacterial cell-wall biosynthesis. The targets were synthesized via a route involving the synthesis of a protected beta-D-arabinofuranosyl phosphate derivative, its coupling with a polyprenyl trichloroacetimidate, and then deprotection of the resulting product. The use of arabinofuranosyl phosphates with the monosaccharide hydroxyl groups protected as either silyl ethers or benzoate esters was explored. Although the coupling yields between the phosphate and polyprenyl trichloroacetimidates were comparable with either type of protecting group, access to the benzoyl-protected derivative was more efficient and therefore gave the products in higher overall yield.     

Bile acid sulfates. I. Synthesis of lithocholic acid sulfates and their identification in human bile

Sulfate esters of lithocholic, glycolithocholic, and taurolithocholic acids were synthesized using sulfur trioxide in pyridine; they were purified by crystallization from methanol or ethanol as the diammonium salts, and their chemical compositions, infared spectra, and chromatographic behavior were determined. Strong alkaline hydrolysis of these sulfates, as commonly performed during quantitative and qualitative analyses of conjugated bile salts, was found to result in a number of degradation products, presumably through disruption of the C-O bond of the hydroxyl group and conversion of the original steroid to isolithocholate and other (possibly olefinic) compounds. After oral administration of lithocholate-(14)C to three patients with cholelithiasis, radioactive metabolites having the chromatographic properties of sulfated lithocholates were isolated from bile and, confirming a preliminary report (1), were identified as sulfated glycolithocholate and taurolithocholate by their characteristic chromatographic mobilities during a series of specific hydrolytic procedures and by crystallizing them to constant specific activities with the synthetic sulfates. The fraction of endogenous lithocholate present in bile as the sulfate was calculated for two patients by isotope dilution and was shown to be 41% and 75% of the total. Sulfation can be expected to affect the physiological and pharmacological properties of lithocholates and may, therefore, influence the toxic properties of these compounds.     

Synthesis and anticoagulant activity of the quaternary ammonium chitosan sulfates

Quaternary ammonium chitosan sulfates with diverse degrees of substitution (DS) ascribed to sulfate groups between 0.52 and 1.55 were synthesized by reacting quaternary ammonium chitosan with an uncommon sulfating agent (N(SO₃Na)₃) that was prepared from sodium bisulfite (NaHSO₃) through reaction with sodium nitrite (NaNO₂) in the aqueous system homogeneous. The structures of the derivatives were characterized by FTIR, ¹H NMR and ¹³C NMR. The factors affecting DS of quaternary ammonium chitosan sulfates which included the molar ratio of NaNO₂ to quaternary ammonium chitosan, sulfated temperature, sulfated time and pH of sulfated reaction solution were investigated in detail. Its anticoagulation activity in vitro was determined by an activated partial thromboplastin time (APTT) assay, a thrombin time (TT) assay and a prothrombin time (PT) assay. Results of anticoagulation assays showed quaternary ammonium chitosan sulfates significantly prolonged APTT and TT, but not PT, and demonstrated that the introduction of sulfate groups into the quaternary ammonium chitosan structure improved its anticoagulant activity obviously. The study showed its anticoagulant properties strongly depended on its DS, concentration and molecular weight.     

Chemoenzymatic synthesis of polyprenyl phosphates

Polyprenyl phosphates, including undecaprenyl phosphate and dolichyl phosphate, are essential intermediates in several important biochemical pathways including N-linked protein glycosylation in eukaryotes and prokaryotes and prokaryotic cell wall biosynthesis. Herein, we describe the evaluation of three potential undecaprenol kinases as agents for the chemoenzymatic synthesis of polyprenyl phosphates. Target enzymes were expressed in crude cell envelope fractions and quantified via the use of luminescent lanthanide-binding tags (LBTs). The Streptococcus mutans diacylglycerol kinase (DGK) was shown to be a very useful agent for polyprenol phosphorylation using ATP as the phosphoryl transfer agent. In addition, the S. mutans DGK can be coupled with two Campylobacter jejuni glycosyltransferases involved in N-linked glycosylation to efficiently biosynthesize the undecaprenyl pyrophosphate-linked disaccharide needed for studies of PglB, the C. jejuni oligosaccharyl transferase.     

Alkyl sulfates and alkyl aryl sulfonates as inhibitors of penicillinase]

The kinetics of inhibition of penicillinase of Bac. licheniformis 749/c by various alkyl-sulphates (with a long hydrocarbon chain from C8 to C16), n-toluolsulphoacid and alkylbenzol-sulphonate (R-C12--C16) was studied. The inhibition rate increased with elongation of the alkyl radical and rising of the inhibitor concentraiton. This means that the determining factor in inhibition process was hydrophobic interaction of the alkyl chains and not the electrostatic interaction with the enzyme. In-vitro experiments with penicillinase-producing strains of staphylococcus showed that non-bactericidal concentrations of the alkylsulphates and alkylben zolsulphonates increased the effect of benzylpenicillin, ampicillin and methicillin. The highest increase in the antibiotic activity, as well as in the enzyme inhibition was observed with respect to the compound with the hydrocarbon chain fron C12 to C16. The increase in the activity of methicillin against the staphylococcal strains resistant simultaneously to benzylpenicillin, ampicillin and methicillin was indicative of possible using of the above surface active substances as inhibitors of the realization process of various mechanisms of penicillin resistance.     

Synthesis of amylose acetates and amylose sulfates with high structural uniformity

Amylose triacetate (ATA) dissolved in DMSO was partially deacetylated by 1,6-hexamethylendiamine, 1,8-octamethylendiamine, 1,12-dodecylmethylendiamine and 1,2-cyclohexyldiamine (mixture of cis and trans isomers) at 80 degrees C. The reaction kinetics of the deacetylation were studied. Differences were found in the course of the reaction depending on the type of alkylene diamine (linear or cyclic). The isolated amylose acetates were dissolved in DMF and subsequently sulfated with sulfamic acid. In the course of the sulfation, the acetyl groups acted as protective groups and were completely cleaved after reaction. The amylose acetates and sulfates obtained were studied by 13C NMR spectroscopy and elemental analysis. It could be shown, that the deacetylation of ATA with the described alkylene diamines as well as the subsequent sulfation are highly regioselective. By proceeding this reaction scheme it is possible to synthesize 6-amyloseacetate, 2,6-di-amyloseacetate and 2-amylosesulfate with a high structural uniformity.     

Lysis of yeast protoplasts under sodium alkyl sulfates treatment]

The lytic action of homologous series of sodium alkyl sulfates on yeast protoplasts was studied. The concentration dependences study allowed to estimate the lytic concentrations C50 of the agents required for the 50% lysis of protoplasts in the suspension. The data concerning the agents micelle formation in the lytic medium allowed to make some suggestions and to produce a model of the lytic action of alkyl sulfates on the plasma membrane of the protoplasts. The amounts of the agents absorbed on the membrane and involved in the interaction followed by the membrane breakdown in the model are evaluated. On the basis of the data obtained it is concluded that sodium dodecyl sulfate displays the highest lytic activity to the yeast protoplast plasma membrane as compared to the other alkyl sulfates used in the study. The results obtained are discussed in terms of the effect of yeast cell wall on the extraction of intracellular proteins from intact yeast cell under sodium alkyl sulfates action.     

Solubilization and properties of polyprenyl phosphate: GDP-D-mannose mannosyl transferase

A soluble enzyme which catalyzes the formation of dolichyl β-d-mannosyl phosphate has been prepared from encysting cultures of Acanthamoeba castellanii. The enzyme is relatively specific for GDP-d-mannose in that GDP-d-glucose and various uridine nucleotides do not serve as substrates. Uridine diphosphate d-glucose is not an inhibitor at 100-fold molar excess concentration, but GDP-d-glucose, GDP, and GMP do inhibit the reaction at relatively high concentrations. The apparent K_m for GDP-d-mannose is approximately 0.25 μm and that for dolichyl phosphate is approximately 3.3 μm. The enzyme has a pH optimum of 7.0, a temperature optimum of 27 °C, and requires a divalent cation. Magnesium, cobalt, and manganese salts will serve as cofactors but maximum activity is produced by Mn²⁺. No loss of activity is evident after storage for 2 weeks at ?70 °C, but half the activity was lost within 3 days at 0 °C, and a third of the activity was lost within 2 weeks at ?20 °C.     

Activation of human spleen glucocerebrosidases by monoacylglycol sulfates and diacylglycerol sulfates

The study of the acidic lipid requirement of human spleen glucocerebrosidase was extended to include two new series of acidic lipids, namely, monoacylglycol sulfates and diacylglycerol sulfates. Lysosomal glucocerebrosidase was extracted with sodium cholate and 1-butanol to render its beta-glucosidase activity dependent upon exogenous lipids. Maximum reactivation of control glucocerebrosidase was obtained with nonanoylglycol sulfate (NGS) and diheptanoylglycerol sulfate (DHGS). However, the effects of these lipids were markedly dependent on the nature of buffer used in the assay medium; specifically, 0.2 M sodium citrate-phosphate (pH 5.5) was much more effective than 0.2 M sodium acetate (pH 5.5) in permitting these lipids to reactivate glucocerebrosidase. In contrast, the marked activation of glucocerebrosidase by phosphatidylserine and galactocerebroside 3-sulfate (sulfatide) that was achievable in the sodium acetate buffer was totally inhibited by citrate or phosphate ions. The effects of NGS and DHGS on the kinetic parameters of control glucocerebrosidase were to lower the Km for the substrate, 4-methylumbelliferyl-beta-D-glucoside from 5.5 mM to approximately 2 mM (in sodium citrate-phosphate buffer) and markedly increase the Vmax. Furthermore, with DHGS, significant activation was achieved at concentrations below the lipid's critical micellar concentration. None of the monoacylglycol- or diacylglycerol sulfates were capable of stimulating mutant glucocerebrosidases from either type 1 (Ashkenazi-Jewish) or type 2 Gaucher's disease patients. Like control glucocerebrosidase, the type 1 glucocerebrosidase was unresponsive to phosphatidylserine and sulfatide when the beta-glucosidase assay was conducted in 0.2 M sodium citrate-phosphate buffer. Based on the differential action of these lipid activators in the two buffers and their effects on the mutant enzymes, we propose that, with regard to the lipid requirement of glucocerebrosidase, there are two classes of acidic lipids--one comprised of phosphatidylserine and sulfatide and the other comprised of the likes of NGS, DHGS, or sodium taurodeoxycholate. It appears that control glucocerebrosidase and the mutant enzyme of the patient with type 1 Gaucher's disease is reconstitutable with the first class of lipids whereas the glucocerebrosidase of the type 2 patient is not. The observations in this report are interpreted in terms of a model which postulates that normal glucocerebrosidase possesses at least two distinct lipid binding domains.     

Synthesis of polyprenyltoluquinols from homogentisate and polyprenyl pyrophosphates in particulate fractions of Euglena and sugar beet (Short Communication)

Chloroplast-rich particles of sugar beet and Euglena gracilis are able to carry out the light-, H(2)O(2)- and O(2)-independent syntheses of a nonaprenyltoluquinol, an octaprenyltoluquinol and a phytyltoluquinol from homogentisate and nonaprenyl, octaprenyl and phytyl pyrophosphate. The formation of these compounds probably takes place by the concomitant polyprenylation (or phytylation) and non-oxidative decarboxylation of homogentisate.     

Aliphatic alcohol sulfates: new polar lipids isolated from various Fucacea]

Four new sulfolipids have been found in the three Fucacea from the coast of Britany P. canaliculata (L) Deen et Thur, F. vesiculosus (L), F. serratus (L). These four polar lipids form a separate group, their structures being very different from those of the glyceride by-products already known. By acid hydrolysis of these substances the aliphatic mono and dialcohols can be separated. The aliphatic hydrocarbons studied by gas chromatography and spectrometric methods (IR, MASS), have been established as being saturated C30 mono or dialcohols, saturated C18 and C20 monoinsaturated dialcohols. SAA are the only substances found: there was no sulfonate or phosphate ester in the three algae studied. The quantity and composition of SAA are not characteristic of the species. Their variations depend on the physiological and biochemical states of the thallus and on the conditions of extraction and purification.     

Isolation and structural studies of heparan sulfates and chondroitin sulfates from three species of molluscs

The isolation and some structural features of heparan sulfates and chondroitin sulfates from three species of molluscs (Pomacea sp., Tagelus gibbus, and Anomalocardia brasiliana) are reported. It is shown that heparan sulfates with structural similarities to the ones found in mammals are present in the three molluscs analyzed. All the heparan sulfates were degraded by heparitinases I and II to four distinct unsaturated disaccharides with the same properties as the ones present in heparan sulfates of mammalian origin. This suggests that these four disaccharide units are maintained through the evolution. Furthermore, the proportion of these units varied in the heparan sulfates according to the species of origin. The chondroitin sulfates, on the other hand, exhibit different structural features according to the species of origin. For instance, by the action of chondroitinase AC, 4- and nonsulfated disaccharides are produced from Pomacea chondroitin, whereas 4- and 6-sulfated disaccharides are formed from Tagelus and Anomalocardia. The possible role of these compounds in cell recognition and/or adhesiveness is discussed in view of the present findings.     

Stimulation of polyprenyl 4-hydroxybenzoate transferase activity by sodium cholate and 3-[(cholamidopropyl)dimethylammonio]-1-propanesulfonate

Polyprenyl 4-hydroxybenzoate transferase (Coq2p) plays a central role in ubiquinone biosynthesis. Coq2p mediates the conjugation of 4-hydroxybenzoate, the benzoquinone ring precursor, with the completed side chain. The activity is most easily assayed by measuring the rate of incorporation of 4-hydroxybenzoate as radiolabeled substrate into polyprenyl 4-hydroxybenzoate. The in vitro assay requires addition of a detergent into the reaction mixture to activate enzyme activity, and Triton X-100 is used for this purpose in the routine assay. We have found that both 3-[(cholamidopropyl)dimethylammonio]-1-propanesulfonate and sodium cholate, but not sodium deoxycholate, lysophosphatidyl choline, or octylglucoside, significantly stimulate the activity over that measured with Triton X-100. High-performance liquid chromatography analysis of lipid extracts revealed that the increase of specific activity resulted in a similar increase in reaction product, this effect is due not merely to a better lipid extraction but also to the actual stimulation of enzyme activity. With our improved method, we were able to measure Coq2p activity with much greater sensitivity in both fresh and frozen/thawed mitochondria and in crude homogenates obtained from cultured cells. Our method will simplify evaluation of Coq2p activity in scarce biological materials, such as cells obtained from human tissue biopsies, and thus it will facilitate the biochemical characterization of ubiquinone deficiencies.     

Mechanism of penicillinase inhibition by alkyl sulfates in the presence of synthetic polyeletrolytes]

Competing inhibition of Bacillus licheniformis 749/C penicillinase by alkylsulfates CnH2n+ 1OSO3N1 where n was 8--16 was studied. The values of the inhibition constants Ki of individual homologues were estimated. It was shown that stability of complex "enzyme-inhibitor" increased with lengthening of the hydrocarbon radical which was probably due to increased hydrophobic interaction of the alkyl radical with the lipophilic areas of the penicillinase active center. Inhibition in the presence of sopolymers of vinylpirrolidone with N-alkylvinylamine was studied with the aim of modeling the process of penicillinase inhibitions by alkylsulfates in the presence of the blood serum. It was shown that polyelectrolytes posessing hydrophobic substituents had an ability of reducing the activity of inhibited penicillinase, cooperative transfer of alkylsulfate molecules from the enzyme to polyelectrolyte being observed. The maximum effect was registered in the polyelectrolytes with substituents C12H25 and C16H33 which was confirmed in the experiments with the penicillinase-producing strains of staphylococci.