Related Experiment Videos
Arginase, an S-phase enzyme in a human cell line
Biochimica Et Biophysica Acta
|January 7, 1981
Summary
Cellular arginase activity fluctuates during the cell cycle, peaking in the S and G2 phases. This variation is driven by changes in enzyme synthesis, not degradation, in synchronized Chang liver cells.
Area of Science:
- Biochemistry
- Cell Biology
- Enzymology
Background:
- Arginase plays a role in amino acid metabolism and urea synthesis.
- Understanding enzyme regulation during the cell cycle is crucial for cell biology.
- Chang liver cells are a human cell line used in research.
Purpose of the Study:
- To investigate the cell cycle-dependent regulation of arginase activity in Chang liver cells.
- To determine the mechanisms controlling arginase synthesis and degradation during cell division.
Main Methods:
- Cell synchronization using glutamine deficiency or thymidine blockade.
- Separation of unsynchronized cells by velocity sedimentation.
- Inhibition of protein synthesis with cycloheximide to assess enzyme synthesis and degradation rates.
Main Results:
- Specific arginase activity was highest during the S and G2 phases of the cell cycle.
- Arginase activity increase was inhibited by cycloheximide, indicating de novo synthesis.
- Enzyme degradation rate was constant (4-6% per hour), suggesting synthesis controls activity variations.
Conclusions:
- Arginase activity in Chang liver cells is regulated by cell cycle-dependent synthesis.
- The enzyme's role in cells lacking a urea cycle warrants further investigation.
- These findings contribute to understanding enzyme regulation in proliferating cells.