Abnormal Neutral Lipase Activity in Acid-Lipase-Deficient Cultured Human Fibroblasts
| Autor: | Matthew W. Spence, Harold W. Cook, Sam Messieh, J.T.R. Clarke |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
chemistry.chemical_classification
biology Cholesterol Hydrolysis Albumin Fatty acid Lipase Cholesterol ester storage disease Phosphatidylserine Fibroblasts Hydrogen-Ion Concentration Lipid Metabolism Inborn Errors chemistry.chemical_compound chemistry Biochemistry Pediatrics Perinatology and Child Health biology.protein Glycerol Humans Cholesterol Esters Triolein Cells Cultured Triglycerides |
| Zdroj: | Pediatric Research. 17:770-774 |
| ISSN: | 1530-0447 0031-3998 |
| Popis: | Acid and neutral lipase activities of homogenized or sonicated cultured fibroblasts were examined using [2-3H]glycerol triolein, glycerol tri[1-14C]oleate or cholesterol [1-14C]oleate as substrates. In normal fibroblasts, optimal conditions for acid lipase activity were pH 4.5–5.0, 0.15–0.2 mM triacylglycerol, and 0.25% Triton X-100. Fatty acid release was linear to 2 h and between 0.2–2.0 mg fibroblast protein/ml. For the neutral lipase, activity was optimal at pH 6.0–7.0, >1.5 mM triacylglycerol or cholesterol oleate (suspended in 8 mg albumin/ml), and 160 μ g phosphatidylserine/ml. The reaction was linear to 60–120 min, and up to 1.0 mg protein/ml. In contrast to the situation at neutral pH, very little [3H]glycerol was released under acid conditions, suggesting little monoglyceride lipase activity at acid pH. Acid lipase activity in fibroblasts from Wolman's disease (WD) or cholesterol ester storage disease (CESD) patients was 75–80% in the WD cells, indicating that low levels of activity measured with the exogenous substrate were not due solely to lack of accessibility to the neutral lipase. These results suggest a close relationship between the acid and neutral activities of the normal cell in that mutations which affect one apparently affect the activity of the other. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|