Metabolism of pyruvate and glyoxylate by eggs of salmon (Salmo salar)

Abstract 1. 1. Eggs of salmon ( Salmo salar ) were incubated at 25°C, in the presence of pyruvate or glyoxylate labeled with 14 C in different positions. 2. 2. Salmon eggs were able to oxidize any carbon atom in the substrates examined, although in treatments with pyruvate C-1 was preferentially oxidized to C-2 or C-3, and in treatments with glyoxylate C-1 was preferentially oxidized to C-2. 3. 3. Lactate was produced from pyruvate or glyoxylate, but the production of lactate was greater from the former than from the latter. 4. 4. Any carbon atom in pyruvate or glyoxylate could be incorporated by eggs into keto-, amino- or other organic acids, lipids, nucleic acids or proteins. 5. 5. The results suggested that salmon eggs were able to fix carbon dioxide with pyruvate and that they metabolized glyoxylate via the glycerate pathway. 6. 6. The formation of 14 C-amino acids from 14 C-pyruvate and -glyoxylate indicated the presence of an active transaminase system in salmon eggs.