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Prolinase activity in prolidase-deficient fibroblasts
1Laboratoire de Biochimie Appliquée, Faculté de Pharmacie, Châtenay-Malabry, France.
Journal of Inherited Metabolic Disease
|January 1, 1988
Summary
Prolidase deficiency leads to increased prolinase activity in skin cells. This compensatory mechanism aims to restore proline levels, crucial for cellular function.
Area of Science:
- Biochemistry
- Cell Biology
- Enzymology
Background:
- Prolidase (EC 3.4.13.9) deficiency is a rare genetic disorder.
- This deficiency impacts proline metabolism and cellular function.
Purpose of the Study:
- To investigate the activity of prolinase (EC 3.4.13.8) in fibroblasts from patients with prolidase deficiency.
- To understand the compensatory mechanisms in response to prolidase deficiency.
Main Methods:
- Cultured skin fibroblasts from three prolidase-deficient patients and eleven controls were used.
- Enzyme kinetics, specifically prolinase activity assays with pro-val substrate and manganese, were performed.
- Michaelis constants (Km) and maximal velocity (Vmax) were determined for prolinase.
Main Results:
- Prolinase activity was significantly higher in prolidase-deficient fibroblasts compared to controls.
- No significant differences in Michaelis constants were observed between deficient and control cells.
- Vmax constants for prolinase increased in deficient fibroblasts for both pro-val and progly substrates.
Conclusions:
- Prolinase activity elevates in prolidase-deficient fibroblasts, suggesting a compensatory response.
- This increased prolinase activity may help to replenish the diminished intracellular proline pool.
- Findings align with observations of elevated prolinase activity in the plasma of patients with prolidase deficiency.