An immunochemical analysis of the novel liver‐restricted LDH activity from cichlid fishes (Cichlidae: Teleostei) confirms its non‐orthology with piscine LDH‐C

Abstract

In an electrophoretic survey of lactate dehydrogenase (LDH) isozymes in neotropical cichlid fishes (Perciformes: Cichlidae) several species were discovered in which a cathodal liver-restricted isozyme is expressed along with the highly anodal eye-restricted isozyme (LDH-C,) typically encountered in perciform fishes. Biochemical characterization of these two isozymes from the basketmouth cichlid, Acuroniu nnssu (Heckel), strongly suggested that they were non-orthologous and challenged the accepted view that eye-and liver-restricted LDH isozymes are alternative expressions of the same (LDH-C*) gene. In this study, antiserum raised against cypriniform (goldfish) liver-restricted LDH-C, failed to cross-react with the basketmouth liver-restricted analogue while effectively titrating the eye-restricted, anodal isozyme and, at higher titres, the LDH-9, heart-restricted isozyme from all cichlid species. Anti-serum raised against basketmouth muscle-restricted LDH-A, failed to titrate any of the eye-and liver-restricted isozymes. These data confirm the orthology of eye-and liver-restricted LDH isozymes in Cypriniform and Perciform fishes as originally proposed, suggest that the liver-restricted isozyme of cichlid fishes is non-orthologous and further raise the question of identity and evolutionary origin of this anomalous LDH activity.

Biochemical Properties of Lactate Dehydrogenase Eye-Specific C4Isozyme: Lepomis macrochirus and Micropterus salmoides

“…Ldh-C는 경골어류의 간이나 눈조직에서 나타나며, 역 학적 특성과 전하도 다르고 다른 유전자에 의해 발현되며 [21,22] 농어목의 눈조직에서 발현되는 LDH eye-specific C4, 잉어목과 대구목의 간조직에서 발현되는 LDH liver-specific C4 및 포유류와 조류의 정소와 정자에서 발현되는 LDH testis-specific C4가 보고되었다. 따라서 왜 Ldh-C를 특정 조직에 서만 필요로 하는지에 대해 확실하지 않지만, LDH C는 유전 적 이점이 있으므로 진화를 통해 보존되어 있는 것으로 받아 들여져 정소의 testis-specific C4에 대해서만 활발히 연구가 진 행되고 있다.…”