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Biomedical subjects

C C Sweeley

Publications and source records attributed to C C Sweeley.

At least 73 records · Page 4Linked to original sources
PubMed1979

Isolation and identification of a fucose-containing ganglioside from bovine thyroid gland.

Bovine thyroid glands are known to contain a complex array of gandliosides. One of the predominant gangliosides was isolated analyzed by gas-liquid chromatography and mass spectrometry. The carbohydrate composition was fucose, N-acetylneuraminic acid, galactose, N-acetylgalactosamine, and glucose in molar ratios of 1:1:2:1:1. The structure of the ganglioside was identified as: (Formula: see text).

Animals↗
PubMed1979

The configuration and location of the ribosidic linkage in the prosthetic group of citrate lyase (Klebsiella aerogenes).

The structure of the prosthetic group of citrate lyase (Klebsiella aerogenes) was studied by nuclear magnetic resonance and mass spectrometry. The spectra at 360 MHz of the nucleoside moiety (2'-ribosyladenosine) show the absence of 2'-hydroxyl proton, thus confirming the 2' position as the site of attachment of the second ribose moiety to the dephospho-CoA. This glycosidic linkage is found to be alpha(1" leads to 2') and is identical to that of poly(ADP-ribose). Studies of permethylation products by mass spectrometry support the above conclusion regarding the location of the ribosidic linkage.

ATP Citrate (pro-S)-Lyase↗
PubMed1979

Enzyme therapy in Fabry disease: differential in vivo plasma clearance and metabolic effectiveness of plasma and splenic alpha-galactosidase A isozymes.

A pilot trial of enzyme replacement with splenic and plasma alpha-galactosidase A (alpha-D-galactosidase; alpha-D-galactoside galactohydrolase, EC 3.2.1.22) isozymes was undertaken in two brothers with Fabry disease, an X-linked glycosphingolipid storage disease. Six unentrapped doses (2000 units/kg) of each isozyme were administered intravenously to the respective recipients during a 117-day period. The circulating half-life of the splenic isozyme was about 10 min, whereas that for the plasma isozyme was approximately 70 min. No immune response was detected by skin and immunodiffusion tests or by alterations in the maximal activity or clearance kinetics for either isozyme after successive administrations. After each dose of the splenic isozyme, the concentration of the accumulated circulating substrate, trihexosylceramide (globotriaosylceramide), decreased maximally (approximately 50% of initial values) in 15 min and returned to preinfusion levels by 2-3 hr. In marked contrast, injection of the plasma isozyme decreased the circulating substrate levels 50-70% by 2-6 hr; the concentrations gradually returned to preinfusion values by 36-72 hr.

Adult↗
PubMed1978

Plasma alpha-galactosidase A:properties and comparisons with tissue alpha-galactosidases.

The human plasma form of alpha-galactosidase A (alpha-D-galactoside galactohydrolase, EC 3.2.1.22) was highly purified and exhibited apparent Km values of 1.9 mM with 4-methylumbelliferyl-alpha-D-galactopyranoside and 0.23 mM with globotriglycosylceramide. Its inhibition with myo-inositol (Ki = 0.29 M) was similar to that observed with alpha-galactosidase A from various tissues. The plasma form of this lysosomal enzyme has a lower molecular weight of 96 600, a lower pI of 3.7 and faster electrophoretic mobility in polyacrylamide gels than the enzyme obtained from human liver. These data and the increased pI obtained after neuraminidase treatment suggest that the plasma form is an isoenzyme with a more highly sialylated carbohydrate moiety than the tissue isoenzymes.

Galactosidases↗
PubMed1978

Pilot scale purification of alpha-galactosidase A from Cohn fraction IV-1 of human plasma.

Human plasma alpha-galactosidase A (alpha-D-galactoside galactohydrolase, EC 3.2.1.22) was purified 7000-fold over plasma levels from Cohn Fraction IV-1. The yield per kg starting material averaged 11 000 units (nmol galactose liberated per h) and the specific activity was about 600 units per mg protein with 4-methylumbelliferyl-alpha-D-galactoside. The ratio of 4-methylumbelliferyl-alpha-galactosidase to ceramide trihexosidase activities was 6.2. Both activities were heat labile and exhibited the same relative mobilities on polyacrylamide gel electrophoresis. Enzymatic activity was stable for at least 4 months at 4 and -20 degrees C. The endotoxin concentration of this preparation averaged 0.26 mg per mg protein.

Galactosidases↗
PubMed1978

Quantitative metabolic profiling based on gas chromatography.

The quantitative metabolic profiles of volatilizable components of human biological fluids, particularly urinary organic acids, is reviewed, with emphasis on the use of gas-chromatography/mass spectrometer/computer systems. Various definitions of metabolic profiling are considered and techniques for obtaining such profiles are discussed. The role of computer processing of such data is examined, and statistical techniques for treating quantitative metabolic profiles are suggested.

Adult↗
PubMed1978

Automated metabolic profiling of organic acids in human urine. I. Description of methods.

We describe a complete procedure for separation and mechanized analysis of organic acids in human urine. The acid fraction of urine is separated by anion-exchange chromatography on diethylaminoethyl-Sephadex. Individual acids are identified and measured by use of a gas-chromatography/mass spectrometer/computer system that can clearly distinguish contributions from at least 150 substances in a single sample. We discuss analytical recoveries, contributions from the sample separation process, stability of stored samples before and after processing, and reproducibility of the extraction procedure.

Autoanalysis↗
PubMed1978

Automated metabolic profiling of organic acids in human urine. II. Analysis of urine samples from "healthy" adults, sick children, and children with neuroblastoma.

Normalized median, minimum, and maximum values (analytical concentration factors) are given for 134 organic acids in urine of nine adult control subjects, five juvenile control subjects, and five children with neuroblastoma. The organic acids, separated by anion-exchange chromatography, were analyzed by a gas chromatograph-mass spectrometer-computer system. Sixty substances in this fraction are positively identified, and, of these, mean absolute concentrations are listed for 20. An additional 81 substances, sought but not found by this method, and 16 other substances found in a subset of these urines by another analytical method, are also listed. Measured retention indices on 5% OV-17 and a selected discriminating ion are given for each of the total of 231 compounds. Results are compared for the three groups of subjects, and the value of normalizing the data is discussed.

Adolescent↗
PubMed1976

Studies on the mechanism of 3-ketosphinganine synthetase.

The biosynthesis of sphinganine and 4-D-hydroxysphinganine was studied in rat liver microsomes and whole cells of yeast (Hansenula ciferri). It was shown in both cases that the condensation of [2,3,3-2H3]serine and palmitic acid yielded long chain bases containing only two deuterium atoms, both of which were located on the terminal (C-1) carbon atom by combined gas-liquid chromatography/mass spectrometry. When the reaction with the liver microsomal system was carried out in 2H2O with the protium species of serine, the sphinganine contained a deuterium atom on C-2. These results suggest that the synthesis of 3-ketosphinganine involves the replacement of the alpha-hydrogen atom and the carboxyl group of serine by a proton from the medium and a palmitoyl group, rather than a previously proposed mechanism in which the alpha-hydrogen of serine is retained. Some stereochemical requirements of 3-ketosphinganine synthetase are discussed.

Animals↗
PubMed1976

A model for ionization mechanisms in field desorption mass spectrometry.

The apparent discrepancy between theory and experimental practices in field desorption mass spectrometry has encouraged a study attempting to focus theoretical concepts more clearly into forms recognizable to the chemical investigator. Preliminary results indicate that best anode temperature for many compounds is independent of the applied voltage throughout the range available on the Varian MAT CH-5 double focusing mass spectrometer with the electron impact-field ionization-field desorption combined source. Studies of mass transfer indicate that desorption of the sample at the best anode temperature occurs in the absence of the applied field and at a rate which is indistinguishable from the rate of desorption in the presence of the field. These results and other observations, have led us to postulate a new mechanism of ion formation, involving chemical attachment reactions in a thin fluidized system. Clearly, the role of the field in this technique must be the subject of continued study.

Ions↗