Heinová D, Blahovec J, Kovác G
Univerzita verterinárskeho lekárstva, Kosice.
Vet Med (Praha). 1994;39(6):287-96.
In the article we describe lactate dehydrogenase-(LD) (EC 1.1.1.27) isoenzyme pattern detected in the sera of pigs at slaughter. The pattern was different from that of normal serum (Fig. 1) and was characterized by the occurrence of an extra LD-fraction in the cathodic site of LD4 (Fig. 2). This fraction was unusual due to its unwillingness to separate by native polyacrylamide gel electrophoresis (PAGE) and took shape of a diffuse zone. The presence of the extra LD-zone caused a proportional decrease in quantitative distribution of the other LD forms, especially LD1 to LD3, in slaughtered pig sera (Tab. I). We examined the homogeneity of an apparent LD5-fraction using gel isoelectric focusing (IEF). We found out that after separation in a gradient of pH (3-9) two to three new extra bands with LD activity appeared in the area with relatively high pH value (pH 9) (Fig. 3). Their localization in the gradient of pH was greatly different from that of true LD molecules, the latter being situated in more acidic area. It is obvious from the finding described above that the diffuse LD-zone, detected in the serum of pigs at slaughter by native PAGE, was in no case a homogeneous protein. Consequently, it eliminates a possibility that the extra LD fraction reflects an increased LD5 activity in serum of affected animals. On the contrary, the IEF showed that the diffuse LD-zone consisted of two to three electrophoretically distinct proteins with relatively high pI values. As these proteins differed in their electrophoretic properties from the true LD isoenzymes we denoted them LD-like proteins. An origin of the unusual LD-like proteins detected in the serum of pigs at slaughter remains unknown for us for the time being.
在本文中，我们描述了在屠宰猪血清中检测到的乳酸脱氢酶（LD）（EC 1.1.1.27）同工酶模式。该模式与正常血清不同（图1），其特征是在LD4的阴极部位出现了一个额外的LD组分（图2）。这个组分很特别，因为它在天然聚丙烯酰胺凝胶电泳（PAGE）中难以分离，呈现为一个弥散区。屠宰猪血清中额外LD区的存在导致其他LD形式，尤其是LD1至LD3的定量分布成比例下降（表I）。我们使用凝胶等电聚焦（IEF）检查了表观LD5组分的同质性。我们发现在pH（3 - 9）梯度中分离后，在相对高pH值（pH 9）的区域出现了两到三条具有LD活性的新的额外条带（图3）。它们在pH梯度中的定位与真正的LD分子有很大不同，后者位于酸性更强的区域。从上述发现可以明显看出，通过天然PAGE在屠宰猪血清中检测到的弥散LD区绝不是一种均质蛋白质。因此，排除了额外LD组分反映受影响动物血清中LD5活性增加的可能性。相反，IEF表明弥散LD区由两到三种电泳性质不同、pI值相对较高的蛋白质组成。由于这些蛋白质在电泳性质上与真正的LD同工酶不同，我们将它们称为类LD蛋白。目前，我们暂时还不清楚在屠宰猪血清中检测到的异常类LD蛋白的来源。
