Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome.
The cerebro-hepato-renal (Zellweger) syndrome is an autosomal recessive disorder biochemically characterized by the absence of morphologically distinguishable peroxisomes. Key enzymes involved in the biosynthesis of ether phospholipids, i.e., dihydroxyacetone phosphate acyltransferase and alkyl dihy...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
1985-07-01
|
| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520343170 |
| _version_ | 1831567547233730560 |
|---|---|
| author | G Schrakamp C F Roosenboom R B Schutgens R J Wanders H S Heymans J M Tager H van den Bosch |
| author_facet | G Schrakamp C F Roosenboom R B Schutgens R J Wanders H S Heymans J M Tager H van den Bosch |
| author_sort | G Schrakamp |
| collection | DOAJ |
| description | The cerebro-hepato-renal (Zellweger) syndrome is an autosomal recessive disorder biochemically characterized by the absence of morphologically distinguishable peroxisomes. Key enzymes involved in the biosynthesis of ether phospholipids, i.e., dihydroxyacetone phosphate acyltransferase and alkyl dihydroxyacetone phosphate synthase, are located in mammalian (micro)peroxisomes. We have previously shown a strikingly reduced activity of dihydroxyacetone phosphate acyltransferase in liver, brain, and cultured skin fibroblasts from Zellweger patients (Schutgens et al. 1984. Biochim. Biophys. Res. Commun. 120: 179-184). We have now extended these investigations by studying alkyl dihydroxyacetone phosphate synthase in cultured human skin fibroblasts. Enzymatic activity was determined by measuring the formation of radioactive alkyl dihydroxyacetone phosphate from palmitoyl dihydroxyacetone phosphate and [1-14C]hexadecanol as substrates. The enzyme was optimally active at pH 8.5 and was stimulated (about 2-3-fold) by the presence of 0.05% (v/v) Triton X-100. The apparent KM values for the enzyme in control fibroblasts amounted to 35 microM for palmitoyl dihydroxyacetone phosphate and 90 microM for hexadecanol. The reaction became inhibited at higher concentrations of both Triton X-100 and palmitoyl dihydroxyacetone phosphate. Control skin fibroblasts showed alkyl dihydroxyacetone phosphate synthase activity of 69 +/- 28 pmol X min-1 X mg-1 (n = 7), while fibroblasts from patients had an activity of only 6.3 +/- 1.7 pmol X min-1 X mg-1 (n = 7). Alkyl dihydroxyacetone phosphate synthase was also found to be deficient in tissue homogenates of Zellweger patients. The specific activity of this enzyme in liver, kidney, and brain homogenates from Zellweger patients was less than 15% of that in the corresponding tissues from controls. |
| first_indexed | 2024-12-17T12:00:24Z |
| format | Article |
| id | doaj.art-95be1713a2ac4faaab4f0f8ae58ad240 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-17T12:00:24Z |
| publishDate | 1985-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-95be1713a2ac4faaab4f0f8ae58ad2402022-12-21T21:49:53ZengElsevierJournal of Lipid Research0022-22751985-07-01267867873Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome.G SchrakampC F RoosenboomR B SchutgensR J WandersH S HeymansJ M TagerH van den BoschThe cerebro-hepato-renal (Zellweger) syndrome is an autosomal recessive disorder biochemically characterized by the absence of morphologically distinguishable peroxisomes. Key enzymes involved in the biosynthesis of ether phospholipids, i.e., dihydroxyacetone phosphate acyltransferase and alkyl dihydroxyacetone phosphate synthase, are located in mammalian (micro)peroxisomes. We have previously shown a strikingly reduced activity of dihydroxyacetone phosphate acyltransferase in liver, brain, and cultured skin fibroblasts from Zellweger patients (Schutgens et al. 1984. Biochim. Biophys. Res. Commun. 120: 179-184). We have now extended these investigations by studying alkyl dihydroxyacetone phosphate synthase in cultured human skin fibroblasts. Enzymatic activity was determined by measuring the formation of radioactive alkyl dihydroxyacetone phosphate from palmitoyl dihydroxyacetone phosphate and [1-14C]hexadecanol as substrates. The enzyme was optimally active at pH 8.5 and was stimulated (about 2-3-fold) by the presence of 0.05% (v/v) Triton X-100. The apparent KM values for the enzyme in control fibroblasts amounted to 35 microM for palmitoyl dihydroxyacetone phosphate and 90 microM for hexadecanol. The reaction became inhibited at higher concentrations of both Triton X-100 and palmitoyl dihydroxyacetone phosphate. Control skin fibroblasts showed alkyl dihydroxyacetone phosphate synthase activity of 69 +/- 28 pmol X min-1 X mg-1 (n = 7), while fibroblasts from patients had an activity of only 6.3 +/- 1.7 pmol X min-1 X mg-1 (n = 7). Alkyl dihydroxyacetone phosphate synthase was also found to be deficient in tissue homogenates of Zellweger patients. The specific activity of this enzyme in liver, kidney, and brain homogenates from Zellweger patients was less than 15% of that in the corresponding tissues from controls.http://www.sciencedirect.com/science/article/pii/S0022227520343170 |
| spellingShingle | G Schrakamp C F Roosenboom R B Schutgens R J Wanders H S Heymans J M Tager H van den Bosch Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome. Journal of Lipid Research |
| title | Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome. |
| title_full | Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome. |
| title_fullStr | Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome. |
| title_full_unstemmed | Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome. |
| title_short | Alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in Zellweger syndrome. |
| title_sort | alkyl dihydroxyacetone phosphate synthase in human fibroblasts and its deficiency in zellweger syndrome |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520343170 |
| work_keys_str_mv | AT gschrakamp alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome AT cfroosenboom alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome AT rbschutgens alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome AT rjwanders alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome AT hsheymans alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome AT jmtager alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome AT hvandenbosch alkyldihydroxyacetonephosphatesynthaseinhumanfibroblastsanditsdeficiencyinzellwegersyndrome |