Structural features of the low-molecular-weight plasma fraction in far eastern redfins of the genus Tribolodon and other cyprinid fishes

Abstract

The organization of the low-molecular fraction (LMF) of proteins from fish plasma was studied in Far Eastern redfins of the genus Tribolodon and other representatives of the family Cyprinidae. The common principle of the organization of the plasma LMF was established. According to this principle, the LMF includes two subfractions, one of which consists of oligomeric and the other of monomeric proteins. During the pre-spawning period, a decrease in the apparent molecular weight of proteins as a result of changes in their oligomeric structure was observed in the former subfraction; a reduction of the heterogeneity of the proteins occurred in the latter one. The analysis of these rearrangements allows one to differentiate two main types of the LMF: “basic” and “plastic.” The former type is characterized by a low level of metabolic processes; the latter one, by their activation during the pre-spawning period. By using MALDI mass spectrometry, polymeric forms of apolipoproteins, fetuin, and albumin-like protein were identified within the oligomeric subfraction; hemopexin and inhibitors of proteinases were found within the monomeric subfraction.