Radiometric assays for glycerol, glucose, and glycogen
- Univ. of Southern California School of Medicine, Los Angeles (USA)
We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with (32P)ATP and glycerokinase, residual (32P)ATP is hydrolyzed by heating in acid, and free (32P)phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays.
- OSTI ID:
- 5046108
- Journal Information:
- Analytical Biochemistry; (USA), Vol. 180:1; ISSN 0003-2697
- Country of Publication:
- United States
- Language:
- English
Similar Records
Radiometric oil well assay for glucokinase in microscopic structures
Biochemical and mathematical modeling of microaerobic continuous ethanol production by Saccharomyces cerevisiae
Related Subjects
GLUCOSE
RADIOASSAY
GLYCEROL
GLYCOGEN
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
ADIPOSE TISSUE
ATP
DOSE-RESPONSE RELATIONSHIPS
IN VITRO
MICE
PHOSPHATES
PHOSPHORUS 32
PHOSPHORYLATION
RATS
TRACER TECHNIQUES
ALCOHOLS
ALDEHYDES
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARBOHYDRATES
CHEMICAL REACTIONS
CONNECTIVE TISSUE
DAYS LIVING RADIOISOTOPES
ENZYMES
HEXOSES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MONOSACCHARIDES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
POLYSACCHARIDES
RADIOISOTOPES
RODENTS
SACCHARIDES
TISSUES
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques