ROLE OF COFACTORS IN BREAKDOWN OF TMAO IN FROZEN RED HAKE MUSCLE

Previously indicated results that cofactor concentrations were the rate-limiting factor in the production of DMA in frozen red hake muscle were confirmed. Both the Fe-reducing agent (ascorbate, cysteine) and the flavin-NADH systems which had been previously shown to be effective in vitro, were demonstrated to also function in minced muscle and in reconstituted muscle, i.e., muscle from which the low molecular weight fraction had been removed. The evidence implies that an oxidation-reduction cycle of Fe is involved in the breakdown of TMAO to DMA. Activity with the flavin system is greatly increased in the presence of glucose oxidase and glucose which would remove O₂ from the system. Fe was effective in increasing DMA production under all conditions, whereas Fe⁺³ was effective only in the presence of reducing agents and/or anaerobic conditions. Enzymes capable of destroying cofactors when added to minced muscle tissue before frozen storage inhibited the rate of formation of DMA. The percentage of formaldehyde produced which was bound (unreactive to the Nash reagent) was much higher in minced muscle than in reconstituted muscle, indicating that a large fraction of the formaldehyde produced reacts with the low molecular weight fraction.