HeLp, a heme lipoprotein from the hemolymph of the cattle tick, Boophilus microplus
HeLp, a heme lipoprotein from the hemolymph of the cattle tick, Boophilus microplus
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DOI：
10.1074/jbc.m007344200
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发表时间：
2000-11-24
影响因子：
4.8
通讯作者：
Oliveira, PL
中科院分区：
文献类型：
--
作者：
Maya-Monteiro, CM;Daffre, S;Oliveira, PL
牛蜱微小牛蜱（Boophilus microplus）血淋巴的主要蛋白质已被分离并显示为血红素脂蛋白（HeLp）。HeLp的表观分子量为354，000，含有两种等量的脱辅基蛋白（103和92 kDa）。HeLp呈现5.8的pi和1.28 g/ml的密度，并且含有33%的脂质（含有中性脂质和磷脂两者）和3%的糖。Help的一个显著特征是胆固醇酯的丰度（占总脂质的35%），这是一种以前在无脊椎动物脂蛋白中没有报道的脂质。Western印迹分析表明，帮助血淋巴从成年女性和男性，但不是在鸡蛋。虽然Help含有2个血红素分子，但它能够结合6个额外的血红素分子。牛蜱喂养大量的血液，我们最近表明，这种蜱是无法进行从头合成血红素（布拉兹，G，R。C.的方法，Coelho，H. S. L.，增田，和Oliveira，P. L.（1999）Curr. 9，703-706）。用Fe-55标记的血红素-HeLp注射蜱雌性表明，该蛋白质将血红素从血淋巴转运到组织。帮助建议是一个必不可少的适应血红素合成途径的损失。
The main protein of the hemolymph of the cattle tick Boophilus microplus has been isolated and shown to be a heme lipoprotein (HeLp). HeLp has an apparent molecular mass of 354,000 and contains two apoproteins (103 and 92 kDa) found in equal amounts. HeLp presents a pi of 5.8 and a density of 1.28 g/ml and contains 33% Lipids, containing both neutral lipids and phospholipids, and 3% of sugars. A remarkable feature of Help is the abundance of cholesterol ester (35% of total lipids), a lipid not previously reported in invertebrate lipoproteins. Western blot analysis showed Help in hemolymph from adult females and males, but not in eggs. Although Help contains 2 heme molecules, it is capable of binding 6 additional molecules of heme. Boophilus feeds large amount of blood, and we recently showed that this tick is unable to perform de novo synthesis of heme (Braz, G, R. C., Coelho, H. S. L., Masuda, H., and Oliveira, P. L. (1999) Curr. Biol. 9, 703-706). Injection of tick females with Fe-55-labeled heme-HeLp indicated that this protein transports heme from hemolymph to tissues. Help is suggested to be an essential adaptation to the loss of the heme synthesis pathway.