Two methods for determining the activity of δ-aminolevulinate synthetase within intact liver cells in culture
Analytical Biochemistry, ISSN: 0003-2697, Vol: 79, Issue: 1, Page: 380-393
1977
- 31Citations
- 2Captures
Metric Options: CountsSelecting the 1-year or 3-year option will change the metrics count to percentiles, illustrating how an article or review compares to other articles or reviews within the selected time period in the same journal. Selecting the 1-year option compares the metrics against other articles/reviews that were also published in the same calendar year. Selecting the 3-year option compares the metrics against other articles/reviews that were also published in the same calendar year plus the two years prior.
Example: if you select the 1-year option for an article published in 2019 and a metric category shows 90%, that means that the article or review is performing better than 90% of the other articles/reviews published in that journal in 2019. If you select the 3-year option for the same article published in 2019 and the metric category shows 90%, that means that the article or review is performing better than 90% of the other articles/reviews published in that journal in 2019, 2018 and 2017.
Citation Benchmarking is provided by Scopus and SciVal and is different from the metrics context provided by PlumX Metrics.
Example: if you select the 1-year option for an article published in 2019 and a metric category shows 90%, that means that the article or review is performing better than 90% of the other articles/reviews published in that journal in 2019. If you select the 3-year option for the same article published in 2019 and the metric category shows 90%, that means that the article or review is performing better than 90% of the other articles/reviews published in that journal in 2019, 2018 and 2017.
Citation Benchmarking is provided by Scopus and SciVal and is different from the metrics context provided by PlumX Metrics.
Metrics Details
- Citations31
- Citation Indexes31
- 31
- CrossRef30
- Captures2
- Readers2
Article Description
Two methods are described by which δ-aminolevulinate synthetase activity is assayed within cultures of intact chick embryo liver cells. The methods depend on blocking further metabolism of δ-aminolevulinate with levulinate (25 m m ). Under these conditions, the δ-aminolevulinate accumulates, much of it leaking out into the medium. The δ-aminolevulinate is measured colorimetrically in a 10-cm light-path cuvette. As little as 0.5 mg of cell protein/assay is required, and the lower limit of the spectrophotometric assay is 600 pmol/2 ml of culture medium. With the first method, the accumulation of δ-aminolevulinate can be followed during the induction, by chemicals, of δ-aminolevulinate synthetase within the intact cell. The second method serves as a quantitative assay for the amount of enzyme present at any one time point. Method 1 is sufficiently sensitive to measure the low activity of the uninduced enzyme as the accumulation of δ-aminolevulinate over a period of 16 hr. With cells in which δ-aminolevulinate synthetase has been chemically induced, method 1 yields a rate of δ-aminolevulinate production by these intact cells, 50–60% of the rate of δ-aminolevulinate produced by homogenates of the same cells incubated in an optimal assay medium. Glycine added to the culture medium at 5 m m increased by three-fold δ-aminolevulinate production by the induced intact cells. With method 2, the enzyme activity of intact cells which have been induced for a defined time, can be measured merely by replacing the culture medium with an “assay medium” containing levulinate (30 m m ), glycine (50 m m ), citrate (5 m m ) and buffer and then incubating the cells for 5 hr. During this time, δ-aminolevulinate accumulates at a linear rate. The rate is equivalent to that of the homogenates of the same cells. The advantage of method 2 compared with the assay of homogenized cells is that the enzyme can be assayed in small amounts of cells without harvesting. One 3.5-cm dish containing 0.7 mg of cell protein is sufficient for one determination.
Bibliographic Details
http://www.sciencedirect.com/science/article/pii/0003269777904122; http://dx.doi.org/10.1016/0003-2697(77)90412-2; http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=0017388537&origin=inward; http://www.ncbi.nlm.nih.gov/pubmed/405884; https://linkinghub.elsevier.com/retrieve/pii/0003269777904122; http://dx.doi.org/10.1016/0003-2697%2877%2990412-2; https://dx.doi.org/10.1016/0003-2697%2877%2990412-2
Elsevier BV
Provide Feedback
Have ideas for a new metric? Would you like to see something else here?Let us know