Singh I, Lazo O, Contreras M, Stanley W, Hashimoto T
Department of Pediatrics, Medical University of South Carolina, Charleston 29425.
Arch Biochem Biophys. 1991 Apr;286(1):277-83. doi: 10.1016/0003-9861(91)90041-g.
Peroxisomes isolated from cultured skin fibroblasts of two patients with rhizomelic chondrodysplasia punctata (RCDP) and two controls were compared for biochemical studies. These experiments provided the following results: (1) peroxisomes isolated from RCDP-cultured skin fibroblasts had the same density (1.175 g/ml) as control peroxisomes; (2) dihydroxyacetone phosphate acyltransferase activity, the first enzyme in the synthesis of plasmalogens, was deficient (0.5% of control) in RCDP peroxisomes and this activity was not observed in any other region of the gradient; (3) the rate of activation (lignoceroyl-CoA ligase) and oxidation of lignoceric acid was normal in RCDP peroxisomes; and (4) peroxisomes from RCDP contained 3-ketoacyl-CoA thiolase in the unprocessed form (44-kDa protein), whereas control peroxisomes had both processed (41-kDa protein) and unprocessed forms of 3-ketoacyl-CoA thiolase. The presence of both processed and unprocessed 3-ketoacyl-CoA thiolase in control peroxisomes and the unprocessed form in RCDP peroxisomes suggests that processing of 3-ketoacyl-CoA thiolase takes place in peroxisomes. Although the specific activity and percentage of activity of 3-ketoacyl-CoA thiolase in RCDP peroxisomes was only 22-26% of control, the normal oxidation of lignoceric acid in RCDP peroxisomes indicates that unprocessed 3-ketoacyl-CoA thiolase is active. The remaining peroxisomal 3-ketoacyl-CoA thiolase activity in RCDP was observed in a protein fraction (peroxisome ghosts) lighter than peroxisomes. The normal oxidation of fatty acids in peroxisomes and the absence of such activity in peroxisome ghosts (d = 1.12 g/ml) containing peroxisomal proteins in RCDP suggest that RCDP has only one population of functional peroxisomes (d = 1.175 g/ml).
对从两名点状软骨发育不良（RCDP）患者及两名对照者的培养皮肤成纤维细胞中分离出的过氧化物酶体进行了生化研究比较。这些实验得出了以下结果：（1）从RCDP培养皮肤成纤维细胞中分离出的过氧化物酶体与对照过氧化物酶体具有相同的密度（1.175克/毫升）；（2）甘油磷酸二羟丙酮酰基转移酶活性，即缩醛磷脂合成中的第一种酶，在RCDP过氧化物酶体中缺乏（为对照的0.5%），且在梯度的任何其他区域均未观察到该活性；（3）RCDP过氧化物酶体中木蜡酸的激活速率（木蜡酰辅酶A连接酶）和氧化正常；（4）RCDP的过氧化物酶体含有未加工形式（44千道尔顿蛋白）的3-酮脂酰辅酶A硫解酶，而对照过氧化物酶体既有加工形式（41千道尔顿蛋白）也有未加工形式的3-酮脂酰辅酶A硫解酶。对照过氧化物酶体中同时存在加工和未加工的3-酮脂酰辅酶A硫解酶，而RCDP过氧化物酶体中只有未加工形式，这表明3-酮脂酰辅酶A硫解酶的加工发生在过氧化物酶体中。尽管RCDP过氧化物酶体中3-酮脂酰辅酶A硫解酶的比活性和活性百分比仅为对照的22 - 26%，但RCDP过氧化物酶体中木蜡酸的正常氧化表明未加工的3-酮脂酰辅酶A硫解酶是有活性的。RCDP中剩余的过氧化物酶体3-酮脂酰辅酶A硫解酶活性在比过氧化物酶体轻的蛋白质组分（过氧化物酶体空壳）中观察到。RCDP中过氧化物酶体中脂肪酸的正常氧化以及在含有过氧化物酶体蛋白的过氧化物酶体空壳（密度 = 1.12克/毫升）中缺乏这种活性，表明RCDP只有一群功能性过氧化物酶体（密度 = 1.175克/毫升）。
