Morishita K, Asano S, Fujii H, Yokota J, Kodo H, Miwa S
J Appl Biochem. 1984 Oct-Dec;6(5-6):271-7.
Myeloperoxidases were purified from leukemic myeloblasts (Mbl-MPO) and from normal neutrophilic granulocytes (Gra-MPO) and were compared with each other biochemically. Gel filtration studies showed that the molecular weights (Mr) of Mbl-MPO and Gra-MPO were about 70,000 and 130,000, respectively, so that the former is almost one-half the molecular size of the latter. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 2-mercaptoethanol, both MPOs split into two major subunits, heavy and light peptide chains. However, each of these chains of Mbl-MPO seemed to be smaller than that of Gra-MPO, Mr 58,000 versus Mr 62,000 for the heavy chain and Mr 12,000 versus Mr 15,000 for the light chain. On the other hand, another band of Mr 34,000 also appeared in Mbl-MPO under nonreducing conditions and in both MPOs after being boiled. The size of this band was not different in the two MPOs, but the ratio of this band to the others was much higher in Mbl-MPO. The activity of Mbl-MPO could be demonstrated in the heavy chain of Mr 58,000, using a blotting method, and was found to be less heat stable than that of Gra-MPO. These findings indicate that Mbl-MPO may represent an incomplete, unstable half-enzyme form of Gra-MPO.
从白血病原始粒细胞（Mbl-MPO）和正常嗜中性粒细胞（Gra-MPO）中纯化髓过氧化物酶，并对其进行生化比较。凝胶过滤研究表明，Mbl-MPO和Gra-MPO的分子量（Mr）分别约为70,000和130,000，因此前者的分子大小几乎是后者的一半。在含有2-巯基乙醇的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳中，两种MPO均分裂为两个主要亚基，即重肽链和轻肽链。然而，Mbl-MPO的每条链似乎都比Gra-MPO的链小，重链的分子量分别为58,000和62,000，轻链的分子量分别为12,000和15,000。另一方面，在非还原条件下，Mbl-MPO中还出现了一条分子量为34,000的条带，在煮沸后的两种MPO中也出现了该条带。这条带在两种MPO中的大小没有差异，但在Mbl-MPO中，这条带与其他条带的比例要高得多。使用印迹法可在分子量为58,000的重链中检测到Mbl-MPO的活性，并且发现其热稳定性低于Gra-MPO。这些发现表明，Mbl-MPO可能代表Gra-MPO的一种不完整、不稳定的半酶形式。
