Olsen R L, Little C
Biochem J. 1984 Sep 15;222(3):701-9. doi: 10.1042/bj2220701.
The subunit composition of human myeloperoxidase was studied with the use of sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration. The subunit pattern observed depended on the manner in which the enzyme was treated before analysis. Reduction before heat treatment in detergent led to two main protein species (Mr 57 000 and 10 500), whereas reduction during or after heat treatment yielded an additional species of Mr 39 000. Heating without any reductive pretreatment yielded the 39 000-Mr form as the major electrophoretic species. Carbohydrate staining showed large amounts of sugar on the 57 000-Mr species and little on the 10 500-Mr form. Significant amounts of haem were associated with this latter subunit. Haem also seemed to be associated with the 57 000-Mr form but not with the 39 000-Mr one. These three subunit forms were isolated and their amino acid composition analysed. The 57 000-Mr and 39 000-Mr forms had very similar amino acid composition and yielded an apparently identical collection of fragments on incubation with CNBr. Once separated, the subunits could not be interconverted. Generally, minor amounts of other molecular-mass forms were observed. The nature of the various molecular-mass forms originating from myeloperoxidase is discussed.
利用十二烷基硫酸钠/聚丙烯酰胺凝胶电泳和凝胶过滤法研究了人髓过氧化物酶的亚基组成。观察到的亚基模式取决于分析前酶的处理方式。在去污剂中热处理前进行还原，产生两种主要蛋白质种类（Mr 57 000和10 500），而在热处理期间或之后进行还原则产生另一种Mr 39 000的种类。未经任何还原预处理进行加热，产生的39 000-Mr形式是主要的电泳种类。碳水化合物染色显示，57 000-Mr种类上有大量糖，而10 500-Mr形式上很少。大量的血红素与后一种亚基相关。血红素似乎也与57 000-Mr形式相关，但与39 000-Mr形式无关。分离出这三种亚基形式并分析其氨基酸组成。57 000-Mr和39 000-Mr形式具有非常相似的氨基酸组成，并且在与溴化氰孵育时产生明显相同的片段集合。一旦分离，这些亚基就不能相互转化。一般来说，还观察到少量其他分子量形式。讨论了源自髓过氧化物酶的各种分子量形式的性质。
