Dataset Information

ENTRY OF GLUCOSE CARBON INTO AMINO ACIDS OF RAT BRAIN AND LIVER IN VIVO AFTER INJECTION OF UNIFORMLY 14-C-LABELLED GLUCOSE.

ABSTRACT: 1. Measurements were made of the rate of incorporation of (14)C from uniformly (14)C-labelled glucose into individual amino acids of rat brain and liver. 2. At 2.5 min. after intravenous injection of uniformly (14)C-labelled glucose, about 30% of the total radioactivity in the brain was present in the five amino acids studied. At 30 min. after subcutaneous injection the distribution of (14)C in amino acids was: in brain, alanine 2%, gamma-aminobutyrate 4%, aspartate 9%, glutamine 9% and glutamate 37% (total 69%); in liver, alanine 3%, aspartate 2.6%, glutamine 5.3% and glutamate 5.2% (total 18%). About 1% of the total radioactivity was in serine and glycine. 3. In both organs the specific radioactivity of alanine was initially higher than that of the other amino acids examined. The specific radioactivity of gamma-aminobutyrate in the brain was about the same as or higher than that of glutamate. 4. Amino acids of the rat brain were separated into ;free' and ;bound' fractions from brain dispersions in saline (or sucrose) media. Definite differences in the specific activities of the ;bound' and ;free' forms were not apparent.

SUBMITTER: GAITONDE MK

PROVIDER: S-EPMC1206516 | biostudies-other | 1965 Feb

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:BackgroundThe use of enriched stable isotopes is of outstanding importance in chemical metrology as it allows the application of isotope dilution mass spectrometry (IDMS). Primary methods based on IDMS ensure the quality of the analytical measurements and traceability of the results to the international system of units. However, the synthesis of isotopically labelled molecules from enriched stable isotopes is an expensive and a difficult task. Either chemical and biochemical methods to produce labelled molecules have been proposed, but so far, few cost-effective methods have been described.ResultsThe aim of this study was to use the microalgae Chlamydomonas reinhardtii to produce, at laboratory scale, 15N-labelled amino acids with a high isotopic enrichment. To do that, a culture media containing 15NH4Cl was used. No kinetic isotope effect (KIE) was observed. The labelled proteins biosynthesized by the microorganism were extracted from the biomass and the 15N-labelled amino acids were obtained after a protein hydrolysis with HCl. The use of the wall deficient strain CC503 cw92 mt+ is fit for purpose, as it only assimilates ammonia as nitrogen source, avoiding isotope contamination with nitrogen from the atmosphere or the reagents used in the culture medium, and enhancing the protein extraction efficiency compared to cell-walled wild type Chlamydomonas. The isotopic enrichment of the labelled amino acids was calculated from their isotopic composition measured by gas chromatography mass spectrometry (GC-MS). The average isotopic enrichment for the 16 amino acids characterized was 99.56 ± 0.05% and the concentration of the amino acids in the hydrolysate ranged from 18 to 90 µg/mL.ConclusionsPreviously reported biochemical methods to produce isotopically labelled proteins have been applied in the fields of proteomics and fluxomics. For these approaches, low amounts of products are required and the isotopic enrichment of the molecules has never been properly determined. So far, only 13C-labelled fatty acids have been isolated from labelled microalga biomass as valuable industrial products. In this study, we propose Chlamydomonas reinhardtii CC503 as a feasible microorganism and strain to produce labelled biomass from which a standard containing sixteen 15N-labelled amino acids could be obtained.

Dataset Information

ENTRY OF GLUCOSE CARBON INTO AMINO ACIDS OF RAT BRAIN AND LIVER IN VIVO AFTER INJECTION OF UNIFORMLY 14-C-LABELLED GLUCOSE.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets