D. Heinova et al., NEW ASPECTS OF LACTATE-DEHYDROGENASE ISOE NZYME PATTERN IN THE SERUM OF PIGS AT SLAUGHTER, Veterinarni medicina, 39(6), 1994, pp. 287-296
In the article we describe lactate dehydrogenase - (LD) (EC 1.1.1.27)
isoenzyme pattern detected in the sera of pigs at slaughter. The patte
rn was different from that of normal serum (Fig 1) and was characteriz
ed by the occurrence of an extra LD-fraction in the cathodic site of L
D4 (Fig. 2). This fraction was unusual due to its unwillingness to sep
arate by native polyacrylamide gel electrophoresis (PAGE) and took sha
pe of a diffuse zone. The presence of the extra LD-zone caused a propo
rtional decrease in quantitative distribution of the other LD forms, e
specially LD1 to LD3, in slaughtered pig sera (Tab. I). We examined th
e homogeneity of an apparent LD5-fraction using gel isoelectric focusi
ng (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 wi
th 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 seru
m of pigs at slaughter by native PAGE, was in no case a homogeneous pr
otein. Consequently, it eliminates a possibility that the extra LD fra
ction 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 hi
gh pI values. As these proteins differed in their electrophoretic prop
erties from the true LD isoenzymes we denoted them LD-like proteins. A
n origin of the unusual LD-like proteins detected in the serum of pigs
at slaughter remains unknown for us for the time being.