Electrophoretic separation and characterization of LDH isozymes in Japanese quail brain

Lactate dehydrogenase isozyme pattern of adult male quail brain was investigated by polyacrylamide-gel electrophoresis followed by densitometry. LDH is a tetramer with two different types of polypeptide chains (subunits) viz. H and M. It exists in different molecular forms with different electrophoretic mobility. Most common LDH isozymes encountered in birds are LDH 1 > LDH 2 > LDH 3 > LDH 4 > LDH 5 (represented in the order of mobility on electro-chromatogram) corresponding to the tetramers H₄M, H₃M, H₂M₂ and M₄ respectively. The distribution of different isozymes is mostly tissue specific according to their function. It was observed that M-type lactate dehydrogenase subunit found predominant in adult male quail brain indicated the tissue favors highly anaerobic conditions. Densitometry analysis confirmed the higher LDH enzyme activity was in the band nearer to the origin of zymogram. Polyacrylamide-gel electrophoresis revealed good resolution and can be used for separation of LDH isozyme in quail and chicken brain as well.