Quantitative determination of urinary neuraminyl oligosaccharides by gas-liquid chromatography

Isolation of Unusually Composed Sialyl-Compounds from Hemofiltrate

Sialyl compounds are essential components of various biological fluids but relatively little is known about their occurrence in the extracellular fluid of patients with end-stage renal disease. As we have developed a macropreparative method for concentrating and desalting a wide range of fractions from diluted biological fluids we have been able to isolate and identify 5 sialooligosaccharides, 3 sialosugarphosphates, 2 monosialoglycopeptides and 1 disialoglycopeptide. The structures have been elucidated predominantly by one and two-dimensional NMR spectroscopy, enzymatic degradation and FAB mass spectrometry.

The accumulation of these compounds in uremic sera may be of particular interest as they may interact in the molecular biology of diseases typically associated with the uremic state, e.g., immune deficiency, neurological disorders, receptor binding abnormalities, complement system disturbances and cell membrane alterations.

Free fatty acids: a stimulus for mucin hypersecretion in cholesterol gallstone biles

The concentration of free fatty acids, phosphatidylcholine and lysophosphatidylcholine, and the fatty acid composition as well as the levels of the mucins, analyzed by an improved GLC method, were examined in ten biles from patients with cholesterol gallstones (pathological biles) and in ten control biles. In pathological biles the amounts of free fatty acids and phosphatidylcholine, were significantly higher (8.99 +/- 1.09) vs. 2.75 +/- 0.62 micrograms/mg) and lower (6.62 +/- 0.71 vs. 21.91 +/- 3.86 micrograms/mg), respectively, than in control biles, indicating that a relationship exists between the two lipid fractions. Lysophosphatidylcholine concentrations remained unchanged in the two groups (1.02 +/- 0.55 micrograms/mg in pathological biles vs. 1.32 +/- 0.57 micrograms/mg in control biles). The increased levels of free fatty acids were directly correlated (r = 0.73, P less than 0.05) with biliary hypersecretion of mucus glycoproteins. Acetylglucosamine and acetylgalactosamine were significantly higher in pathological biles than in control biles (1.91 +/- 0.67 vs. 0.60 +/- 0.13 microgram/mg). The nucleating potency of the increased amounts of mucins, coupled with lowered levels of phosphatidylcholine, might play a very important role in stone formation and precipitation.

Isolation and structural characterization of five major sialyloligosaccharides and a sialylglycopeptide from normal human urine

Five major sialyloligosaccharides and a sialylglycopeptide have been isolated from normal human urine by charcoal adsorption, gel filtration, ion-exchange chromatography, and paper chromatography. Structural studies including gas-liquid chromatography of monosaccharide and disaccharide derivatives, methylation analysis, glycosidase treatments, and CrO3 oxidation indicated the following structures for the compounds: 1, NeuAc(alpha 2-6)Gal(beta 1-4)Glc; 2, NeuAc(alpha 2-6)Gal(beta 1-4)GlcNAc; 3, NeuAc(alpha 2-3)Gal(beta 1-4)Glc; 4, NeuAc(alpha 2-3)Gal(beta 1-4) GlcNAc; 5, NeuAc(alpha 2-3)Gal(beta 1-3) [Neu-Ac(alpha 2-6)]GalNAc; and 6, NeuAc(alpha 2-3)Gal(beta 1-3) [NeuAc(alpha 2-6)]GalNAc (alpha 1-O)Ser. Compounds 4, 5, and 6 have not been described in a free form before. The presence of compound 5 in urine may suggest that it derives from glycoproteins through a catabolic pathway involving cleavage of the carbohydrate-peptide linkage by an endo-N-acetylgalactosaminidase. The predominating sialyloligosaccharides in urine were compounds 3 and 4. The predominance of the compounds with the sialyl(alpha 2-3) linkage is of interest in view of the recent discovery of uropathogenic Escherichia coli strains with binding specificity for sialyl(alpha 2-3)galactosides.

Relationship between urinary sialylated saccharides, serum amyloid A protein, and C-reactive protein in rheumatoid arthritis and systemic lupus erythematosus

The urinary excretion of sialic-acid-containing oligosaccharides, total sialic acid, serum amyloid A protein (SAA), and C-reactive protein (CRP) has been studied in 48 patients with rheumatoid arthritis (RA) and in 17 patients with systemic lupus erythematosus (SLE). Linear regression analysis revealed a close positive correlation between serum SAA and CRP levels in both RA (r = 0.71, p less than 0.001) and SLE (r = 0.86, p less than 0.001). The urinary excretion of sialyl lactose showed a positive correlation with the serum levels of SAA and CRP in RA (r = 0.45 and r = 0.45, respectively, p less than 0.01) but not in SLE (r = 0.05 and r = 0.10 respectively). Changes in serum total sialic acid levels paralleled those in CRP and SAA in RA as well as in SLE. Patients with very active RA had higher urinary sialyl oligosaccharide excretion (p less than 0.001), higher CRP levels (p less than 0.01), and higher SAA levels ( p less than 0.05) than those with moderately active disease.

Urinary excretion of sialic acid-containing saccharides in systemic lupus erythematosus

Urinary sialic acid-containing trisaccharides, total sialic acid, and serum sialic acid were studied in 17 patients with systemic lupus erythematosus (SLE) and in 15 healthy controls. The urinary excretion of sialyllactose, measured by a gas chromatographic method, was significantly greater in patients with SLE (37.4 +/- 21.4 mg/24 hours, SD) than in the control subjects (13.7 +/- 3.8 mg/24 hours, p less than 0.001). The mean excretion of sialyl-N-acetyllactosamine (16.6 +/- 8.5 mg/24 hours) and total sialic acid (82.5 +/- 29.4 mg/24 hours) was also greater in the SLE group than in the controls (8.7 +/- 2.8 and 58.0 +/- 16.0 mg/24 hours, respectively; p less than 0.01). Serum levels of sialic acid were correspondingly higher in the SLE patients (84.4 +/- 20.4 mg/100 ml) than in the controls (63.7 +/- 6.5 mg/100 ml, p less than 0.001). Urinary excretion of sialyl-lactose correlated positively with clinical disease activity (p less than 0.001) and with anti-DNA antibody levels (p less than 0.05). On the average, patients with moderate or severe disease excreted three times more sialyl-lactose than did those with mild or inactive disease. Our results suggest that the excretion of sialyl-oligosaccharides reflects disease activity in SLE.

Urinary sialic acid levels in aspartylglycosaminuria

Urinary sialoglycoconjugates were studied in 22 patients with inherited deficiency of 1-aspartamido-beta-N-acetylglucosamine amidohydrolase (aspartylglycosaminuria), in eight obligate heterozygotes, and in age- and sex-matched control subjects. Total sialic acid excretion was significantly higher in the patients (38.3 +/- 17.7 mumol/mmol creatinine, mean +/- S.D.) than in the matched controls (17.7 +/- 7.3 mumol/mmol creatinine, p less than 0.001). The sialic acid output in the heterozygotes did not differ from that of the controls. Gel filtration studies revealed that the increase in urinary sialic acid in aspartylglycosaminuria is of bound type and confined to the low molecular mass region. A linear positive correlation was found between the output of sialic acid and glycoasparagine in the individual patients (r = 0.77, p less than 0.001). The amount of sialylated metabolites excreted in urine did not correlate with the severity of clinical manifestations in aspartyl-glycosaminuria.

Urinary sialyloligosaccharide excretion as an indicator of disease activity in rheumatoid arthritis

Urinary trisaccharides containing sialic acid, urinary total sialic acid, and serum sialic acid were studied in 51 patients with rheumatoid arthritis (RA). The urinary excretion of sialyllactose and sialyl-N-acetyllactosamine was measured by quantitative gas chromatography. The output of sialyllactose was significantly greater in patients with RA (31.9 +/- 17.3 mg/24, SD) than in control subjects (15.9 +/- 5.4, P less than 0.001). The RA patients also had higher mean levels of urinary sialyl-N-acetyllactosamine (P less than 0.05), total urinary sialic acid (P less than 0.001), and serum sialic acid (P less than 0.001). Urinary excretion of sialyllactose was considerably higher in patients with active and aggressive RA and moderately higher in patients with moderate disease activity. Excretion in those with mild or almost inactive RA did not differ significantly from that in the controls. Linear regression analysis revealed a strong positive correlation between urinary sialyllactose levels and clinical disease activity (P less than 0.001), as well as between excretion of sialyllactose and sialyl-N-acetyllactosamine in RA. These results suggest that the urinary content of trisaccharides containing sialic acid is an indicator of disease activity of RA.

Increased excretion of two sialic acid-containing trisaccharides in the urine of patients with rheumatoid arthritis

The urinary excretion of sialic acid-containing trisaccharides in patients with active rheumatoid arthritis was studied. Sialyl-lactose and sialyl-N-acetyllactosamine were identified and their excretion patterns studied by thin layer and gas chromatography. The urinary output of sialyl-lactose was greater in patients with active rheumatoid arthritis (48.2 +/- 6.1 mg/24 h, SEM, n = 6) than in healthy subjects (19.8 +/- 3.7 mg/24 h, SEM, n = 5; P less than 0.01). The excretion of sialyl-N-acetyllactosamine was also higher in the rheumatoid group (18.5 +/- 2.1 mg/24 h, SEM, n = 6) than in the controls (11.1 +/- 1.2 mg/24 h, SEM, n = 5; P less than 0.05). The qualitative excretion patterns of the sialyl-oligosaccharide fraction were similar for the two groups as judged from the thin layer chromatograms. Correlating the results with the clinical state of the patients with rheumatoid arthritis suggests that the urinary level of the sialyl-oligosaccharides reflects the activity of the disease. A proposed mechanism for the increased excretion of sialic acid-containing trisaccharides in rheumatoid arthritis is presented.

Partial purification of human intestinal alkaline phosphatase with affinity chromotography. Some properties and interaction of concanavalin A with alkaline phosphatase

1. Alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) from human intestine was purified with concanavalin A-Sepharose and tyraminyl derivative-Sepharose affinity chromatography. The enzyme obtained with these techniques had a specific activity of approx. 513.2 mumol p-nitrophenylphosphate hydrolyzed per min per mg of protein at pH 10.0. 2. The highly purified enzyme showed one major enzymatically active band and a possible minor enzymatically active band on acrylamide gel and cellogel electrophoresis, and the two fraction types showed identical antigenicity. 3. The highly purified intestinal enzyme was compared with the purified hepatic enzyme: the saccharide content of each showed a marked difference. 4. The interaction of alkaline phosphatase with concanavalin A, a carbohydrate-binding protein, was studied. Concanavalin A showed an organ-specific behavior to alkaline phosphatase isoenzyme, i.e., the effect on the enzyme activity, and the optimum pH of the activity. 5. The concanavalin A and alkaline phosphatase complex showed a protective effect against heat denaturation and inactivation of proteinase digestion. There was no difference in stability between the intestinal enzyme and the hepatic enzyme. 6. Alkaline phosphatase preparations from human intestine and human liver can bind with concanavalin A; these interactions of concanavalin A; these interactions of concanavalin A with the enzyme occurred reversibly when alpha-methyl-D-mannoside was added. 7. The double reciprocal plots of 1/v vs. 1/s at higher concentrations of concanavalin A showed that the mechanism of inhibition was "mixed type". From the results of Dixon plots, the inhibition constant (Ki) was calculated to the 0.025 muM for human intestinal enzyme. 8. The effect of concanavalin A on L-phenylalanine inhibition of the intestinal alkaline phosphatase indicates that concanavalin A does not interfere with L-phenylalanine binding, but its effect on L-homoarginine inhibition of the hepatic enzyme seems to show that concanavalin A interfered with L-homoarginine binding.

Excretion of neuraminic acid-containing trisaccharides in the urine during pregnancy

The excretion of neuraminic acid-containing trisaccharides in the urine during the course of normal pregnancy was studied. Neuraminyl-lactose and neuraminyl-galactosyl-(l led to 4)-N-acetylglucosamine were identified, and their excretion patterns were analyzed by thin-layer and gas chromatography. A progressive increase in the outputs of these acidic oligosaccharides was observed during the course of pregnancy in all cases studied. Neuraminyl-lactose excretion increased threefold, from 13.7 +/- 1.75 to 37.1 +/- 2.56 mg/24 h, and neuraminyl-galactosyl-N-acetylglucosamine twofold, from 8.4 +/- 1.27 to 15.3 +/- 2.21 mg/24 h (Mean +/- S.E.).

Partial purification and some properties of human liver alkaline phosphatase

1. Alkaline phosphatase (EC 3.1.3.1) from human liver was solubilized from the homogenate using 0.2% Triton X-100 containing 0.2 M lithium 3,5-diiodosalicylate, and the pellet obtained was resolubilized with 20% n-butanol. The procedure resulting in 3842-fold purification included acetone fractionation, ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex G-200 gel filtration, hydroxyapatite gel chromatography and further concanavalin A/Sepharose 4B affinity chromatography. 2. The highly purified enzyme showed one major protein band on acrylamide gel electrophoresis at pH 8.6, and exhibited one-seventh of the alkaline p-nitrophenylphosphatase activity in the hepatic enzyme preparation contains of the alkaline pyrophosphatase activity. 3. The highly purified enzyme was a sialic-acid containing glycoprotein. 4. Sialidase-treated hepatic enzyme clearly presented the phenomenon of delayed mobility, and the delayed enzyme fraction stained more strongly than that of non-treated hepatic alkaline phosphatase. 5. In order to investigate the role of the carbohydrate region(s) of the hepatic alkaline phosphatase molecule on substrate binding, the effect of sialidase treatment on the rate of substrate inhibition of alkaline phosphatase was studied. In the case of hepatic enzyme without sialidase, substrate inhibition of alkaline phosphatase activity was clearly shown, while in the case of the hepatic enzyme with sialidase, there was hardly any substrate inhibition in the range of 1-8 mM p-nitrophenylphosphate.

Structure of the O-glycosidically linked carbohydrate units of rat brain glycoproteins

The O-glycosidically linked carbohydrate units of rat brain glycopeptides were released as reduced oligosaccharides with NaOH/NaBH4 treatment. Five oligosaccharides were isolated using gel filtration, ion-exchange chromatography and preparative thin-layer chromatography. Studies employing periodate oxidation, methylation analysis, chromium trixide oxidation and gas-liquid chromatography-mass spectrometry indicated the following structures: (I) alpha-galactosyl-(1 leads to 3)-N-acetylgalactosaminitol, (II) beta-galactosyl-(1 leads to 3)-N-acetylgalactosaminitol, (III) N-acetylneuraminyl-[beta-galactosyl-(1 leads to 3)-N-acetylgalactosaminitol], (IV) N-acetylneuraminyl-(2 leads to 3)-beta-galactosyl-(1 leads to 3)-N-acetylgalactosaminitol and (V) N-acetylneuraminyl-(2 leads to 3)-beta-galactosyl-(1 leads to 3)[N-acetylneuraminyl-(2 leads to 6)]-N-acetylgalactosaminitol.