SEARCH AND IDENTIFICATION OF OSMOTICALLY ACTIVE PROTEINS IN THE BLOOD SERUM OF ATLANTIC COD GADUS MORHUA

Abstract

A search for osmotically active proteins (OAPs) in the blood serum of the Atlantic cod Gadus morhua was undertaken using polyacrylamide gel electrophoresis methods. OAPs were identified using MALDI mass spectrometry. The results showed the presence of multiple OAPs in the anodic fraction of cod serum, among which hemopexins, inhibitors of serine proteinases and apolipoproteins in the composition of high density lipoproteins dominate. Minor OAPs were represented mainly by intracellular proteins. The osmot-ically active protein albumin, characteristic of mammals, was not found in cod's blood serum. The results of the work confirm the provisions of the “albumin-free” hypothesis of capillary exchange (Andreeva, 2020), which considers multiple proteins of different functional classes as osmotically active protein factors in the plasma of “albumin-free” teleost fish.