Schepers L, Van Veldhoven P P, Casteels M, Eyssen H J, Mannaerts G P
Katholieke Universiteit Leuven, Afdeling Farmacologie, Belgium.
J Biol Chem. 1990 Mar 25;265(9):5242-6.
Mammalian liver peroxisomes are capable of beta-oxidizing a variety of substrates including very long chain fatty acids and the side chains of the bile acid intermediates di- and trihydroxycoprostanic acid. The first enzyme of peroxisomal beta-oxidation is acyl-CoA oxidase. It remains unknown whether peroxisomes possess one or several acyl-CoA oxidases. Peroxisomal oxidases from rat liver were partially purified by (NH4)2SO4 precipitation and heat treatment, and the preparation was subjected to chromatofocusing, chromatography on hydroxylapatite and dye affinity matrices, and gel filtration. The column eluates were assayed for palmitoyl-CoA and trihydroxycoprostanoyl-CoA oxidase activities and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results revealed the presence of three acyl-CoA oxidases: 1) a fatty acyl-CoA oxidase with a pI of 8.3 and an apparent molecular mass of 145 kDa. The enzyme consisted mainly of 52- and 22.5-kDa subunits and could be induced by clofibrate treatment; 2) a noninducible fatty acyl-CoA oxidase with a pI of 7.1 and an apparent molecular mass of 427 kDa. It consisted mainly, if not exclusively, of one polypeptide component of 71 kDa; and 3) a noninducile trihydroxycoprostanoyl-CoA oxidase with a pI of 7.1 and an apparent molecular mass of 139 kDa. It consisted mainly, if not exclusively, of one polypeptide component of 69 kDa. Our findings are probably related to the recent discovery of two species of acyl-CoA oxidase mRNA in rat liver (Miyazawa, S., Hayashi, H., Hijikata, M., Ishii, N., Furata, S., Kagamiyama, H., Osumi, T., and Hashimoto, T. (1987) J. Biol. Chem. 262, 8131-8137) and they probably also explain why in human peroxisomal beta-oxidation defects an accumulation of very long chain fatty acids is not always accompanied by an excretion of bile acid intermediates and vice versa.
哺乳动物肝脏过氧化物酶体能够对多种底物进行β-氧化，包括极长链脂肪酸以及胆汁酸中间体二羟和三羟粪甾烷酸的侧链。过氧化物酶体β-氧化的第一种酶是酰基辅酶A氧化酶。过氧化物酶体是否拥有一种或几种酰基辅酶A氧化酶仍不清楚。通过硫酸铵沉淀和热处理对大鼠肝脏的过氧化物酶体氧化酶进行部分纯化，然后将制剂进行色谱聚焦、羟基磷灰石色谱、染料亲和基质色谱以及凝胶过滤。对柱洗脱液进行棕榈酰辅酶A和三羟粪甾烷酰辅酶A氧化酶活性测定，并通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳进行分析。结果显示存在三种酰基辅酶A氧化酶：1）一种脂肪酸酰基辅酶A氧化酶，其pI为8.3，表观分子量为145 kDa。该酶主要由52 kDa和22.5 kDa的亚基组成，可通过氯贝丁酯处理诱导产生；2）一种不可诱导的脂肪酸酰基辅酶A氧化酶，其pI为7.1，表观分子量为427 kDa。它主要（如果不是唯一的话）由一个71 kDa的多肽组分组成；3）一种不可诱导的三羟粪甾烷酰辅酶A氧化酶，其pI为7.1，表观分子量为139 kDa。它主要（如果不是唯一的话）由一个69 kDa的多肽组分组成。我们的发现可能与最近在大鼠肝脏中发现的两种酰基辅酶A氧化酶mRNA有关（宫泽，S.，林，H.， Hijikata，M.，石井，N.，古田，S.，蒲生山，H.，大隅，T.，和桥本，T.（1987年）《生物化学杂志》262，8131 - 8137），并且它们可能也解释了为什么在人类过氧化物酶体β-氧化缺陷中，极长链脂肪酸的积累并不总是伴随着胆汁酸中间体的排泄，反之亦然。
