Baghiani A, Harrison R, Benboubetra M
Laboratory of Applied Biochemistry, Faculty of Sciences, University of Setif, Algeria.
Arch Physiol Biochem. 2003 Dec;111(5):407-14. doi: 10.3109/13813450312331342265.
Xanthine oxidoreductase (XOR) was purified in the presence of dithiothrietol from camel milk with yields of up to 22.2mg/l that were comparable to those obtained from bovine and human milk sources. On SDS-PAGE, the freshly purified camel milk XOR had a protein flavin (A280/A450) ratio of 5.3 +/- 0.4 and appeared homogenous with a single major band of approximately Mr 145.3 KDa. Surprisingly, in all the batches (n = 8) purified camel milk XOR showed no detectable activity towards xanthine or NADH. The molybdenum content of camel XOR was comparable to human and goat milk enzymes. After resulphuration, camel milk XOR gave a specific activity of 1.1 nmol/min/mg and 13.0 nmol/min/mg enzyme towards pterin (fluorimetric assay) and xanthine (spectrophotometric assay) respectively. This activity was markedly lower than that of human, bovine and goat enzymes obtained under the same conditions. These findings suggest that the molybdo-form of camel enzyme is totally under desulpho inactive form. It is possible that camel neonates are equipped with an enzymic system that reactivates XOR in their gut and consequently generates antibacterial reactive oxygen species.
在二硫苏糖醇存在的情况下，从骆驼奶中纯化出黄嘌呤氧化还原酶（XOR），产量高达22.2毫克/升，这与从牛乳和人乳中获得的产量相当。在十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳（SDS - PAGE）中，新纯化的骆驼奶XOR的蛋白质黄素（A280/A450）比率为5.3±0.4，呈现单一主要条带，分子量约为145.3 kDa，看起来具有均一性。令人惊讶的是，在所有批次（n = 8）中，纯化的骆驼奶XOR对黄嘌呤或烟酰胺腺嘌呤二核苷酸（NADH）均未显示出可检测到的活性。骆驼XOR的钼含量与人和山羊奶中的酶相当。再硫化后，骆驼奶XOR对蝶呤（荧光测定法）和黄嘌呤（分光光度测定法）的比活性分别为1.1纳摩尔/分钟/毫克和13.0纳摩尔/分钟/毫克。该活性明显低于在相同条件下获得的人、牛和山羊的酶的活性。这些发现表明骆驼酶的钼形式完全处于脱硫无活性形式。骆驼新生儿可能配备有在其肠道中使XOR重新激活并因此产生抗菌活性氧的酶系统。
