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PubMed1990

Micellar bile salt mobile phases for the liquid chromatographic separation of routine compounds and optical, geometrical, and structural isomers.

Aqueous solutions of bile salts, i.e. sodium cholate (NaC), sodium deoxycholate (NaDC), and sodium taurocholate (NaTC), are characterized and evaluated as reversed-phase liquid chromatographic (RPLC) mobile phases. The separation of the ASTM-recommended RPLC test mix in addition to more than 50 other compounds on a C18 column demonstrates the viability of these bile salts as HPLC mobile phases. The Armstrong-Nome theory was applied and found to adequately describe the partitioning behavior of solutes eluted with these bile salts at low surfactant concentrations. The effect of alcohol additives on chromatographic retention and efficiency was also assessed. Not only are the bile salt molecules rigid and chiral, but they form helical micellar aggregates as well. Consequently, many isomeric compounds can be easily resolved with this mobile phase additive. The base-line resolution of some binaphthyl-type enantiomers with a standard C18 column and the bile salt micellar mobile phases is also demonstrated. In addition, these bile salt mobile phases may be preferable to conventional hydroorganic mobile phase systems for the separation of many classes of routine compounds. A brief prospectus on the future utilization of bile salts in liquid chromatography is presented.

Bile Acids and Salts↗

PubMed1990

Dose response to a dietary oat bran fraction in cholesterol-fed rats.

The two objectives of this research were to improve the cholesterol-fed rat as a model for evaluating the hypocholesterolemic potential of foods and to determine the relationship between serum and liver lipid levels in the cholesterol-fed rat and the ingestion of nine levels of a high fiber oat flour (HFOF) derived from oat bran. Ingestion of 0.2% cholic acid, sodium cholate or sodium taurocholate with 1% cholesterol (CH) significantly elevated serum and liver CH, liver triglycerides and liver weight compared to those values in control rats fed diets not containing CH and bile acids; 0.05 and 0.1% cholic acid with 1% CH were also effective. Ingestion of increasing amounts of HFOF, containing 0-10% dietary fiber, by rats made hypercholesterolemic with 1% CH and 0.1% cholic acid in the diet produced a significant inverse relationship between serum and liver cholesterol levels and HFOF intake; r = 0.48, p less than 0.0001 for serum CH and r = 0.55, p less than 0.0001 for liver CH. Because of the similarities in the responses of humans and of the cholesterol-fed rat to oat fiber ingestion, this dose-response relationship in the rat model suggests that larger intakes of soluble oat fiber sources may be accompanied by greater reduction in serum CH levels in humans.

Animals↗

PubMed1983

Chemical nature of protein complex of photoreaction unit including reaction center in chromatophores of photosynthetic bacterium, Rhodospirillum rubrum, as detected by successive dissociation method.

Reaction center of chromatophores of Rhodospirillum rubrum consists of three kinds of protein, H-, M-, and L-subunit, and is bound with many other kinds of protein to form a larger protein complex (PRU; photoreaction unit), which contains all the bacteriochlorophyll. In the present study, purified PRU was dissociated in a stepwise manner in the presence of various mixtures of lithium dodecyl sulfate, sodium cholate and/or sodium deoxycholate, and separated into five, smaller protein complexes (PL1, PL2, PL3, PL4, and PL4') by high-speed molecular-sieve chromatography. The protein complexes were analyzed for molecular mass (Mm), protein composition, and molecular weights of the constituent proteins by the chromatography described above and by lithium or sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results suggest that PRU consisted of 1 molecule each of 40K, 39K, 31K (H-subunit), 25K (M-subunit), and 22K (L-subunit), about 12 molecules each of 12K (light-harvesting bacteriochlorophyll-protein) and 11K, and about 6 molecules each of 10K and 9K (the protein nomenclature refers to the apparent molecular weights); the measured and calculated Mm values were 650K and 547K, respectively. The compositions of the other protein complexes were as follows. PL1 = PRU-10K-9K (measured & calculated Mm, 520K & 409K); PL2 = PL1-39K (340K & 267K); PL3 = PL2-40K (160K & 147K); PL4 = PL3-31K-25K (90K & 82K); PL4' = 31K + 25K + 22K (inactivated reaction center) (90K & 78K). The molar ratios of 12K and 11K to 25K were lower in the dissociated protein complexes than in PRU, and they differed from one complex to another. The locations of the constituent proteins in PRU are discussed.

Bacterial Chromatophores↗

PubMed1975

Human milk lipases. III. Physiological implications of the bile salt-stimulated lipase.

Human milk contains a bile salt-stimulated lipase in amounts that, at pH 6.5 and in the presence of bile salts, might account for a total hydrolysis of the milk triacylglycerols in less than 30 min. In the absence of bile salts the enzyme has no activity against milk fat or against emulsified trioleylglycerol. The primary bile salts sodium cholate and sodium chenodeoxycholate and their taurine and glycine conjugates, but not the secondary bile salt sodium deoxycholate or its taurine and glycine conjugates, caused a pronounced activation of the enzyme against emulsified trioleylglycerol. The lipase was stable at pH 3.5 and 37 degrees C for 1 hour. It was inactivated when incubated with trypsin or chymotrypsin at pH 6.5 but these inactivations were almost abolished in the presence of bile salts. High concentrations of pepsin slowly inactivated the enzyme at pH 4.0. The bile salt-stimulated lipase in human milk is thus stable enough to be active in the intestine, and it is present in high enough activity to contribute significantly to the hydrolysis of the milk triaclyglycerols in the intestine.

Bile Acids and Salts↗

PubMed1996

ATP synthesis by the F0F1 ATP synthase from thermophilic Bacillus PS3 reconstituted into liposomes with bacteriorhodopsin. 1. Factors defining the optimal reconstitution of ATP synthases with bacteriorhodopsin.

Optimal conditions for the reconstitution of bacteriorhodopsin and H+-transporting ATP synthase from thermophilic Bacillus PS3 (TF0F1) were determined. Phosphatidylcholine/phosphatidic acid liposomes prepared by reverse-phase evaporation were treated with various amounts of Triton X-100, octyl glucoside, octaethylene glycol n-dodecylether, sodium cholate or sodium deoxycholate and the incorporation of proteins by these detergents was studied at each step of the solubilization process. After removal of detergent by means of SM-2 Bio-Beads, the light-driven ATP synthase activities of the resulting proteoliposomes were analyzed at 40 degrees C. The nature of the detergent used for reconstitution was important for determining the mechanism of protein insertions. The most efficient reconstitutions were obtained with octyl glucoside or Triton X-100 by insertion of the proteins into detergent-saturated liposomes. The conditions for reconstitutions were further optimized with regard to functional coupling between bacteriorhodopsin and TF0F1. It was demonstrated that one of the main factors limiting the production of efficient reconstituted proteoliposomes was related to activation of the highly stable TFO-F1. Activation was accomplished by total solubilization of phospholipids and proteins in a Triton X-100/octyl glucoside mixture containing 20 mM octyl glucoside, leading to a threefold stimulation of the ATP synthase activity. Final ATP synthase activities depended greatly on the lipid/bacteriorhodopsin and the lipid/TF0F1 ratios as well as on the phospholipid used. In particular, light-driven ATP synthesis depended upon the presence of negatively charged phospholipids. Cholesterol was found to induce a fourfold increase in ATP synthase activity with a concomitant 65% decrease in the Km for ADP, suggesting that sterols can modulate catalytic events mediated by F1. Preparations obtained by this step-by-step reconstitution procedure displayed activities up to 20-fold higher (500-800 nmol ATP x min(-1) x mg TF0F1(-1) in the presence of cholesterol) than the maximal values reported in the literature for light-driven ATP synthesis TF0F1 measured under similar conditions. This study also allowed rationalization of the different parameters involved in reconstitution experiments and the present simple method is shown to be of general use for preparation of efficient proteoliposomes containing bacteriorhodopsin and choloroplast or mitochondrial F0F1-type ATP synthases.

Adenosine Triphosphate↗

PubMed1980

Experimental scrapie in the mouse: electrophoretic and sedimentation properties of the partially purified agent.

Some biochemical and biophysical properties of the scrapie agent in a partially purified fraction P5 from murine spleen are described in this communication. The agent was stable in the nonionic detergents Triton X-100 and Nonidet P40 and stable in the nondenaturing, anionic detergents sodium cholate and sodium N-lauroyl sarcosinate. In contrast, sodium dodecyl sulfate (SDS) inactivated the agent at high concentrations (1% or >) when the detergent-to-protein ration approached 1.5 g SDS/g protein. The agent was resistant to inactivation by nucleases and proteases, even in the presence of 0.1% SDS. A broad peak of infectivity was exhibited in modified colloidal silica (Percoll) density gradients. Maximal titers were found at a Percoll density of 1.10 g/cm3 in the presence and absence of 0.05% SDS. Gel electrophoresis of the agent in the presence of 0.1% SDS resulted in inactivation of > 95% of the agent loaded onto the gel. Free-flow electrophoresis showed that > 99% of the agent in fraction P5 migrated toward the anode, but not as a discrete species. Sedimentation analysis of the agent in fraction P5 in the presence of 1% lysolecithin showed that the agent has a sedimentation coefficient of < 300S but > 30S. Heating P5 preparations caused the agent to associate with cellular elements and form aggregates with sedimentation coefficients > 10,000S. Removal by differential centrifugation of the large forms of the agent produced upon heating permitted characterization of a discrete subpopulation of scrapie agent particles. Rate-zonal sucrose gradient studies showed that > 95% of the infectivity in this subpopulation sedimented as uniform particles with a sedimentation coefficient of 240S.

Animals↗

PubMed1978

Acetylsalicylic acid hydrolase of gastric mucosa.

Acetylsalicylic acid hydrolase activity of rabbit fundic gastric mucosa has been isolated from the soluble 100,000 X g supernate. The enzymatic activity was partially purified by ammonium sulfate precipitation. The Km for acetylsalicylate was 2 mM and pH optimum was 8.6. The activity was insensitive to ionic strength, slightly inhibited by inclusion of 100 mM Cl-, and demonstrated no requirement for Ca2+ or Mg2+. Acetylsalicylic acid esterase was markedly inhibited by sodium cholate and sodium dodecyl sulfate. The enzyme was insensitive to sulfhydryl reagents with the exception of p-chloromercuribenzenesulfonic acid, which markedly inhibited the enzyme. Diisopropyl fluorophosphate (DFP) inhibited enzymatic activity with a Ki of 9 X 10(-9)M. Eserine was also inhibitory with a Ki of 0.25 mM. Inhibition by DFP at low concentration and by eserine at millimolar concentrations suggests that this enzyme is related to the group of aliphatic esterases. Identification of potent inhibitors will enable studies to define the role of this enzyme with the use of experimental preparations in which systemic toxicity can be avoided.

Animals↗

PubMed2005

Quantitative estimation of the effects of bile salt surfactant systems on insulin stability and permeability in the rat intestine using a mass balance model.

The oral delivery of peptides and proteins is compromised by chemical and proteolytic instability as well as by permeability limitations. The aim of this study was to delineate the relative contributions of simple bile salt and bile salt:fatty acid mixed micellar systems to protein stability vs permeability enhancement in the rat intestine. Insulin disappearance from the rat intestine was evaluated when administered in simple micellar systems of sodium cholate (NaC), sodium taurocholate (NaTC) and sodium glycocholate (NaGC), and in mixed micellar systems of these bile salts and linoleic acid (LA). In-vitro stability studies were used to evaluate the extent of insulin degradation in the different micellar systems. After correction for insulin degradation in all systems a mass balance model was used to estimate the fractions of insulin absorbed for all systems. Mass balance estimates for the extent of insulin absorption in control perfusion systems were consistent with previously reported predictions of the model for ileal insulin absorption. Mass balance estimates for NaGC suggested no significant effects on the fraction of insulin absorbed relative to control. However, insulin absorption was estimated to occur to a significantly greater extent for NaTC simple micellar systems and was coincident with increased permeability of the hydrophilic marker molecule PEG 4000. The mass balance model estimated higher fractions of insulin absorbed for all mixed micellar systems in line with enhanced plasma insulin levels and higher PEG 4000 permeabilities for these systems.

Animals↗

PubMed1983

Solubilisation and molecular characterisation of muscarinic acetylcholine receptors.

Stable, soluble preparations of rat brain muscarinic receptors can be prepared by extracting membranes with digitonin, or with combinations of sodium cholate and sodium chloride. The stability of the cholate/NaCl extract is enhanced by the addition of egg phosphatidylcholine, which, at the same time, suppresses the considerable dispersity apparent in the hydrodynamic behaviour of the solubilised receptor. The Stokes radius of the brain muscarinic receptor in cholate/NaCl/lecithin extracts is 6.7 nm, with very similar values in other detergents, including digitonin and sodium dodecyl sulphate. Its sedimentation coefficient is 3.78s, and its molecular weight approximately 110,000 after correction for detergent binding. The isoelectric point of the digitonin - solubilised receptor is approximately 4.5.

Animals↗

PubMed1992

Toxic effect of bile acid ingestion in rats.

Ingestion of raw bile from some grass carp fish has been reported to be associated with impairment of renal function in some Chinese people. 5 alpha-cyprinol, the main bile alcohol in these fish, has been suggested as the toxic compound causing electrolyte imbalance. In this study, we attempted to determine whether oral administration of pure bile acids also affects the electrolyte balance in rats. Twenty-four female Long-Evans rats weighing 200-250 g were used. Conscious cannulated animals were prepared and studied with gastric intubation of 15%, 4.8 mL/kg of sodium cholate (SC), sodium deoxycholate (SD), and water; there were three groups of eight rats in each. A drastic drop in blood pressure, elevation of the ST segment of the EKG, increases in plasma potassium, hydrogen, blood urea nitrogen, and oxygen partial pressure were found. All rats treated with bile acids died within 24 hours. Six SD rats and three SC rats died within eight hours after oral administration of bile acid. It is concluded that the effects of feeding rats bile acids are very similar to the toxic action seen after ingestion of grass carp bile.

Animals↗

PubMed1989

Lipid metabolism and low molecular weight solute uptake in Ascaridia galli.

Adult Ascaridia galli, an intestinal nematode parasite of fowl, reveals a large variety of complex lipids such as phospholipids containing choline, ethanolamine, inositol, serine and glycerol. Lysophospholipid species, vinyl ether phospholipid (plasmalogen), neutral acylglycerols, cholesterol and non-esterified fatty acids are also present. Sugar-containing lipids, such as cerebrosides, sulphatides and gangliosides are abundantly present. Female parasites contain more lipids, particularly acylglycerols and phospholipids. Acylglycerols, phosphatidyl choline, phosphatidyl ethanolamine and glycolipids incorporate a large amount of radiolabelled precursor substrate in A. galli. The presence of important enzymes of lipid biosynthesis like glucose-6-phosphate dehydrogenase, malate dehydrogenase and hydroxymethyl glutaryl-CoA reductase as well as an enzyme of lipid ester hydrolysis, triacylglycerol lipase is detected in the parasite. These enzymes show subcellular distribution patterns and Michaelis-Menten kinetic characteristics comparable with that from rat liver homogenate. Studies on the uptake of labelled precursor molecules for lipid biosynthesis, glucose, acetate and palmitate show that the parasites can take up the isotopes readily in a time-dependent manner, showing substrate saturation kinetics, dependence upon Na ions, and can be inhibited by the presence of the bile salts sodium cholate and sodium deoxycholate. The substrate affinity constant (Kt) and maximum apparent velocity of glucose uptake in A. galli were found to be 9.09 mM and 26.67 mM per 100 mg tissue dry weight per min at 37 degrees C.

Acetates↗

PubMed1988

Purification and characterization of a membrane-associated phospholipase A2 from rat spleen. Its comparison with a cytosolic phospholipase A2 S-1.

A membrane-associated phospholipase A2 was purified from rat spleen. The phospholipase A2 was solubilized from the 108,000 x g pellet fraction with 0.3% lithium dodecyl sulfate and then purified to homogeneity by successive DEAE-Cellulofine AM, octyl-Sepharose, Cellulofine GCL 300-m, S-Sepharose, and Bio-Gel P-30 chromatographies in the presence of 0.5% 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonate. The apparent Mr of the enzyme, estimated on sodium dodecyl sulfate polyacrylamide gel electrophoresis, was about 13,600. The purified enzyme had a pH optimum in the range of pH 8.0-9.5 and required the presence of Ca2+ (4 mM) for its maximal activity. The enzyme preferentially hydrolyzed the 2-acyl ester bonds of phosphatidylglycerol in the presence and absence of sodium cholate or sodium deoxycholate. Unlike the phospholipase A2 of rat spleen supernatant, no immunocross-reactivity was observed between the purified enzyme and anti-rat pancreatic phospholipase A2 antibody. The N-terminal amino acid sequence of the enzyme was determined and found to be homologous to that of viperid and crotalid venom phospholipases A2. The results in this and the preceding report (Tojo, H., Ono, T., Kuramitsu, S., Kagamiyama, H., and Okamoto, M. (1988) J. Biol. Chem. 263, 5724-5731) demonstrate that rat spleen contains two genetically distinct phospholipase A2 isoenzymes.

Amino Acid Sequence↗

PubMed1985

Properties of rat liver N-acylethanolamine amidohydrolase.

Rat liver microsomes and mitochondria contain an amidohydrolase which catalyzes the hydrolysis of N-acylethanolamine to ethanolamine and fatty acid. The enzyme is active over a wide range of pH, does not require divalent cations, and is inhibited by sulfhydryl-reactive agents. The detergents Triton X-100, sodium cholate, and sodium dodecyl sulfate are also inhibitory, but sodium taurodeoxycholate has little effect and was therefore used to solubilize the enzyme. The solubilized enzyme exhibits high substrate specificity for long-chain amides of ethanolamine. Amides of propanolamine or higher homologs are hydrolyzed at a drastically slower rate, and isomers prepared from long-chain amine and short-chain hydroxy acid are neither substrates nor inhibitors of the enzyme. Neither ceramide (N-acylsphingosine) nor N,O-diacylethanolamine is hydrolyzed. Both particulate and soluble enzyme preparations also catalyze the synthesis of N-acylethanolamine from ethanolamine and fatty acid, probably by the amidohydrolase acting in reverse.

Amidohydrolases↗

PubMed1980

Action of ortho- and paramyxovirus neuraminidase on gangliosides. Hydrolysis of ganglioside GM1 by Sendai virus neuraminidase.

The action of neuraminidase of influenza A virus, Sendai virus and Newcastle disease virus particles on bovine brain ganglioside GM1 and the properties of Sendai virus neuraminidase for GM1 were studied. With Sendai virus, GM1 was hydrolyzed to asialo-GM1 (GA1) and N-acetylneuraminic acid even in the absence of surfactant or other additives, while the hydrolysis of GM1 by Newcastle disease virus or influenza A virus was very low or undetectable under the same conditions. The formation of GA1 by Sendai virus neuraminidase was confirmed by thin-layer chromatography and immunodiffusion test using anti-GA1 antiserum. The apparent Km of Sendai virus neuraminidase for GM1 hydrolysis was found to be 2.67 x 10(-4) M and the optimum pH was 5.6. GM3, GM2 and oligosaccharide of GM1 were hydrolyzed more effectively than GM1 in the absence of surfactant (GM3 greater than GM2 greater than oligosaccharide of GM1 greater than GM1). The hydrolysis of GM1 by the Sendai virus enzyme was stimulated by the addition of sodium cholate or sodium taurocholate, but was inhibited by divalent cations (10 mM), Ca2+, Mg2+, ZN2+, Fe2+ and CU2+. In the absence of the surfactant, Sendai virus neuraminidase hydrolyzed GM1 more efficiently than Arthobacter ureafaciens neuraminidase which has been reported recently as being an adequate enzyme to hydrolyze ganglioside GM1 as a substrate.

Animals↗

PubMed1996

A novel method for the preclinical assessment of rectal irritation.

The purpose of this study concerns a novel method for preclinical assessment of rectal irritation caused by suppositories introduced into the rectum. Rectal irritation was assessed by the balloon method in fasting conscious rats. This method is based on measuring rectal contractions due to possible irritation caused by the presence of drugs and adjuvants in the suppository. In control experiments (vehicle only), significant rectal contractions were not observed in a range of pH 1.5-11.0 and osmotic pressure 70-2000 mOsm kg-1 H2O, respectively. On the other hand, strong contractions were observed after rectal administration of an aqueous solution of 50% glycerin, 100 mM sodium caprate or 25 mM sodium cholate. The intensity of contraction after rectal administration of sodium caprate or sodium cholate was dependent on the concentration in the dosing solution. In addition, the effect of sodium caprate and sodium cholate on rat rectal mucosa was investigated by optical light microscopy. Although slight or moderate alteration such as the presence of mucinous substance in lumen and congestion, oedema and haemorrhage of the rectal membrane 20 min after rectal administration, there was no major damage to the rectal mucosa. There was a correlation between the median score for mucinous substance in lumen and mean intensity of rectal contraction. For comparative purposes, defecating sensations, pain, itch, burning sensations, and awareness of the presence of a foreign body after administration of suppositories containing 0, 1, 2 and 4% sodium caprate were examined in eight healthy volunteers. The defecating sensation in the human subjects correlated with the intensity of rectal contraction in rats. The results suggest that rectal contraction in conscious rats could be a useful index for prediction of a defecating sensation in man.

Adult↗

PubMed1996

Separation of pharmaceutically important estrogens by micellar electrokinetic chromatography.

Baseline separation of ten estrogens of the type found in conjugated estrogens tablets from pregnant mares' urine were separated by micellar electrokinetic chromatography with a 20 mM sodium borate-sodium phosphate buffer (pH 8) containing either 75 mM sodium cholate and 15 mM beta-cyclodextrin or 50 mM sodium dodecyl sulfate and 20 mM gamma-cyclodextrin. The system containing sodium cholate was used to identify estrogens in a pharmaceutical tablet formulation of conjugated estrogens and to determine the amounts and ratio of sodium equilin sulfate to sodium estrone sulfate to confirm tablet conformity with regulatory requirements. Baseline separation of the seven ethynyl steroids registered as oral contraceptives in the USA was obtained with the system 20 mM sodium borate-sodium phosphate buffer (pH 8) containing 50 mM sodium cholate and 10% (v/v) methanol. Factors that affect selectivity and reproducibility of the above separation systems are discussed.

Animals↗

PubMed2000

Oestradiol skin delivery from ultradeformable liposomes: refinement of surfactant concentration.

The aims of this study were to refine ultradeformable liposomes for oestradiol skin delivery and to evaluate Span 80 and Tween 80 as edge activators compared with sodium cholate. Vesicles containing phosphatidylcholine (PC) mixed with edge activators and oestradiol were prepared. Entrapment efficiency and vesicle size were determined. Interactions between activators and vesicles were investigated using differential scanning calorimetry. Transepidermal permeation of oestradiol from vesicles was studied compared to saturated aqueous control in vitro. The maximum flux (J(max)) and its time (T(max)) were calculated from the flux curves and skin deposition was assessed. The compositions of refined formulations were predicted, liposomes prepared, and tested against control. Entrapment efficiency depended on PC concentration with some contribution from sodium cholate and Tween 80. Vesicle sizes ranged from 124 to 135 nm. Edge activators interacted with lipid bilayers and disrupted packing. The refined edge activator concentrations in PC vesicles were 14.0, 13.3 and 15.5% w/w for sodium cholate, Span 80 and Tween 80, respectively; they increased J(max) by 18, 16 and 15-fold and skin deposition by 8, 7 and 8-fold compared with control. Ultradeformable vesicles thus improved skin delivery of oestradiol compared to control and Span 80 and Tween 80 were equivalent to sodium cholate as edge-activators.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1985

Studies on the interaction of Clostridium perfringens sialidase with sialic acid linked to the internal galactose in monosialogangliotetraosyl ceramide.

Investigation of the action of highly purified Clostridium perfringens sialidase on ganglioside II3Neu5Ac-Gg4Cer and its oligosaccharide II3Neu5Ac-Gg4, in the presence and absence of sodium cholate, extend earlier results obtained with impure enzyme fractions. Sialidase labeled with 125I was found to bind to various ganglioside substrate micelles, including II3Neu5Ac-Gg4Cer, and to mixed ganglioside-sodium cholate micelles. No binding occurred between the enzyme and the ganglioside-derived oligosaccharide II3Neu5Ac-Gg4, even when radioactive II3Neu5Ac-Gg4-[3H]ol was used. The binding of sialidase to micellar substrate is a condition for enzymic hydrolysis. Correspondingly, II3Neu5Ac-Gg4Cer and II3Neu5Ac-Gg4Cer-sodium cholate micelles were hydrolyzed by the enzyme but II3Neu5Ac-Gg4 was not. Ganglioside oligosaccharide analogues containing an amino function at the reducing terminus or between two oligosaccharide chains, II3Neu5Ac-Gg4-NH2 and (II3Neu5Ac-Gg4)2NH, were hydrolyzed in the absence of cholate. A synthetic analogue of II3Neu5Ac-Gg4Cer containing only the fatty acid moiety and not the sphingosine residue (I1-deoxy-I1-stearamido-II3-monosialo-gangliotetraitol ) behaved as the ganglioside in the presence and absence of sodium cholate.

Chemical Phenomena↗