A biochemical characterization of vitellogenins isolated from the marine fish ocean pout ( Macrozoarces americanus L.), lumpfish ( Cyclopterus lumpus) and Atlantic cod ( Gadus morhua)

Abstract

Vitellogenins (VTGs) were isolated from three marine teleosts, the ocean pout ( Macrozoarces americanus), lumpfish ( Cyclopterus lumpus) and Atlantic cod ( Gadus morhua), for the analysis of amino-acid composition and other partial biochemical characterizations. All three VTGs contained high levels of essential amino acids, arginine (5.08–6.54%), lysine (8.44–8.74%), isoleucine (5.60–6.82%), leucine (9.61–11.39%) and valine (6.76–6.99%). While histidine (2.27–2.67%) levels were low, the levels of methionine (1.51–3.38%), threonine (4.69–6.09%) and phenylalanine (3.38–4.41%) varied between species. In the category of non-essential amino acids, aspartic acid (8.60–9.68%), serine (6.09–7.68%), glutamic acid (11.45–11.97%) and alanine (6.49–7.79%) were predominant. Similarity was also noted in the VTG content of protein-bound phosphorus (0.62–0.72%) as well as total lipid (17.92–21.34%) among the three species. However, the molecular weights (485–630 KD), total phosphorus (2.15–3.56%) and the lipid-bound phosphorus contents (1.51–2.86%) of the VTGs varied. VTGs from the Atlantic cod and lumpfish did not cross-react with the antibodies made against ocean pout VTG, suggesting that VTG is species-specific.