Biosynthesis of lipoxygenase products by enzyme preparations from normal and psoriatic skin.
Biosynthesis of lipoxygenase products by enzyme preparations from normal and psoriatic skin.
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通过正常和牛皮癣皮肤的酶制剂生物合成脂氧合酶产品。
DOI：
10.1111/1523-1747.ep12273519
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Voorhees,JJ
中科院分区：
文献类型：
--
作者：
Ziboh,VA;Casebolt,TL;Marcelo,CL;Voorhees,JJ
[14C]花生四烯酸（[14C]AA）与来自银屑病患者的正常、临床受累和未受累表皮的无细胞制剂一起培养，可形成几种放射性标记的脂氧合酶途径代谢物。采用薄层色谱法在两种溶剂体系中分别与正品12l -羟基-5,8,10,14-二十碳四烯酸（12-HETE）和正品5S， 12r -二羟基- 6,8,10,14 -二十碳四烯酸（LTB4）进行比较，确定了12-脂氧合酶和5-脂氧合酶途径产物单羟基- etes和二羟基- etes的性质；采用硅酸柱色谱法和正相、直相高压液相色谱法。催化这种转化的酶的活性定位于表皮制剂的可溶性（105,000 g上清）部分。这两种途径的酶活性均被已知的脂氧合酶和环氧合酶途径的抑制剂5,8,11,13-二十碳四氰酸（ETYA）和非二氢胍酸（NDGA）抑制。临床累及银屑病表皮的可溶性制剂将[14C]AA转化为[14C] ltb4样代谢物显著高于未累及的配对可溶性制剂或正常受试者的可溶性制剂（p < 0.001）。此外，未参与的可溶性制剂的ltb4样代谢物的生物合成显著高于正常表皮制剂（p < 0.05）。这些结果表明，临床涉及的可溶性制剂生物合成的[14C] ltb4样代谢物至少部分是由于病变酶活性的增加，而不完全是由于可能的表皮内浸润中性粒细胞。因此，人表皮制剂中含有催化标记的AA转化为ltb4样代谢物以及其他尚未识别的二羟基- etes的酶。可溶性5-脂氧合酶样活性在表皮的定位表明，脂氧合酶产物可能在该组织的增殖和炎症过程中起作用。
Incubations of [14C]arachidonic acid ([14C]AA) with cell-free preparations from normal, clinically involved and uninvolved epidermis from psoriatic subjects resulted in the formation of several radiolabeled metabolites of the lipoxygenase pathway. The identities of the monohydroxy-ETEs and dihydroxy-ETEs (products of the 12-lipoxygenase and 5-lipoxygenase pathways) were determined by comparison with authentic standards of 12L-hydroxy-5,8,10,14-eicotetraenoic acid (12-HETE) and authentic 5S,12R-dihydroxy-6,8,10, 14-eicosatetraenoic acid (LTB4) by thin-layer chromatography in two solvent systems; by silicic acid column chromatography and by normal phase and straight phase high-pressure liquid chromatography. Activity of the enzymes which catalyze this transformation are localized in the soluble (105,000 g supernatant) fraction of the epidermal preparations. The activity of enzymes of both pathways were inhibited by 5,8,11,13-eicosatetraynoic acid (ETYA) and nor-dihydroguaretic acid (NDGA), known inhibitors of the lipoxygenase and cyclooxygenase pathways. Transformation of [14C]AA into [14C]LTB4-like metabolite by the soluble preparations from clinically involved psoriatic epidermis was significantly higher (p < 0.001) than from paired uninvolved soluble preparations or from soluble preparations from normal subjects. Furthermore, biosynthesis of LTB4-like metabolite by the uninvolved soluble preparation was significantly higher (p < 0.05) than preparations from normal epidermis. These results imply that the [14C]LTB4-like metabolite biosynthesized by the clinically involved soluble preparation was due at least in part to the increased activity of the lesional enzymes and not entirely due to possible intraepidermal infiltrating neutrophils. Human epidermal preparations, therefore, contain enzymes which catalyze the transformation of labeled AA into LTB4-like metabolite as well as into other yet unidentified dihydroxy-ETEs. Localization of a soluble 5-lipoxygenase-like activity in the epidermis implies a possible role of the lipoxygenase products in the proliferative and inflammatory processes in this tissue.