Nelles L P, Schnebli H P
Hoppe Seylers Z Physiol Chem. 1982 Jul;363(7):677-82. doi: 10.1515/bchm2.1982.363.2.677.
Rats produce 2 alpha-macroglobulin (alpha M) proteinase inhibitors, the alpha 1 M, normally found in the plasma, and the alpha 2 M, an acute phase protein. The alpha-macroglobulins were purified from the plasma of rats with adjuvant arthritis by polyethylene glycol precipitation, chromatography on a Zn2+ affinity column, and filtration on Sephacryl S-300 superfine. Comparison of the purified proteins on sodium dodecyl sulfate polyacrylamide gel electrophoresis following reduction reveals a 185 000 Da subunit for rat alpha 2 M identical to the human alpha 2 M, but a 167 000 plus a 38 000 Da subunit for rat alpha 1 M. Heat/alkali treatment (pH 11, 37 degrees C for 45 min) prior to reduction results in the appearance of 125 000 Da and 60 000 Da components from rat alpha 2 M analogous to the pattern of human alpha 2 M. In contrast, alpha 1 M showed in addition to the 125 000 Da band (and the unaltered 38 000 Da band), two bands of approx. 25 000 Da. Incubation with trypsin (approximately 1 mol/mol alpha M) prior to reduction causes formation of approximately 90 000 Da components from both rat inhibitors and the human alpha 2 M. The data suggests that only rat alpha 2 M and not rat alpha 1 M is structurally homologous to human alpha 2 M.
大鼠产生两种α-巨球蛋白（αM）蛋白酶抑制剂，即通常存在于血浆中的α1M和急性期蛋白α2M。通过聚乙二醇沉淀、锌离子亲和柱层析和Sephacryl S-300超细凝胶过滤从佐剂性关节炎大鼠的血浆中纯化α-巨球蛋白。还原后在十二烷基硫酸钠聚丙烯酰胺凝胶电泳上对纯化蛋白进行比较，结果显示大鼠α2M有一个185 000 Da的亚基，与人α2M相同，但大鼠α1M有一个167 000 Da加上一个38 000 Da的亚基。还原前进行热/碱处理（pH 11，37℃，45分钟）会使大鼠α2M出现125 000 Da和60 000 Da的组分，类似于人α2M的模式。相比之下，α1M除了有125 000 Da的条带（以及未改变的38 000 Da条带）外，还有两条约25 000 Da的条带。还原前用胰蛋白酶孵育（约1摩尔/摩尔αM）会使两种大鼠抑制剂和人α2M都形成约90 000 Da的组分。数据表明，只有大鼠α2M而不是大鼠α1M在结构上与人α2M同源。
