Hajra A K, Horie S, Webber K O
Neuroscience Laboratory, University of Michigan, Ann Arbor 48109.
Prog Clin Biol Res. 1988;282:99-116.
Peroxisomes (microbodies) are ubiquitous subcellular organelles whose functions in cellular metabolism are not clear. In recent years peroxisomes have been shown to play roles in the oxidation of long chain fatty acids and ether lipid biosynthesis. The key enzymes of the acyl DHAP pathway i.e. DHAP acyltransferase and alkyl DHAP synthase have been shown to be localized in peroxisomes indicating that these organelles are obligatory for the biosynthesis of cellular glycerol ether lipids. This is proved by the discovery that in the tissues of patients suffering from Zellweger cerebrohepatorenal syndrome, an autosomal recessive disorder where peroxisomes are known to be absent, the acyl DHAP pathway enzymes and the ether lipids were also found to be deficient. Based on such biochemical abnormalities a number of similar genetic disorders such as neonatal adrenoleukodystrophy, different forms of chondrodysplasia punctata, infantile Refsum disease etc. have been characterized as peroxisomal deficiency disorders. These and other findings show that peroxisomes have a regulatory role in membrane lipid biogenesis. It seems that the main role of peroxisomes is to compartmentalize biochemical reactions which cannot proceed in other cellular organelles either due to formation of toxic product (H2O2) or due to non-availability of crucial metabolite (DHAP). The products of the reactions catalyzed by the peroxisomal enzymes e.g. acetyl CoA or alkyl DHAP are then transported out from peroxisomes to other cellular compartments where they are utilized to produce fatty acids, cholesterol, glycerol ether lipids etc. for membrane biogenesis.
过氧化物酶体（微体）是普遍存在的亚细胞细胞器，其在细胞代谢中的功能尚不清楚。近年来，过氧化物酶体已被证明在长链脂肪酸氧化和醚脂生物合成中发挥作用。酰基二羟丙酮磷酸（DHAP）途径的关键酶，即DHAP酰基转移酶和烷基DHAP合酶，已被证明定位于过氧化物酶体，这表明这些细胞器对于细胞甘油醚脂的生物合成是必不可少的。这一点已通过以下发现得到证实：在患有泽尔韦格脑肝肾综合征（一种已知不存在过氧化物酶体的常染色体隐性疾病）的患者组织中，也发现酰基DHAP途径的酶和醚脂缺乏。基于这些生化异常，许多类似的遗传疾病，如新生儿肾上腺脑白质营养不良、不同形式的点状软骨发育不良、婴儿型雷夫叙姆病等，已被归类为过氧化物酶体缺乏症。这些以及其他发现表明，过氧化物酶体在膜脂生物合成中具有调节作用。过氧化物酶体的主要作用似乎是将那些由于形成有毒产物（H2O2）或由于关键代谢物（DHAP）不可用而无法在其他细胞器中进行的生化反应分隔开来。然后，由过氧化物酶体酶催化的反应产物，如乙酰辅酶A或烷基DHAP，从过氧化物酶体转运到其他细胞区室，在那里它们被用于生成脂肪酸、胆固醇、甘油醚脂等用于膜生物合成。
