Biochemical properties of molybdenum cofactor isolated from fish liver.

Recent studies have demonstrated that the fish liver protein fraction extract obtained by gel filtration exhibits nitric oxide synthase (NOS)-independent NO synthase from nitrates and nitrites. This activity was attributed to the molybdenum enzymes (Mo-enzymes) group which was already demonstrated in mammals. However, the evidence that NOS-independent NO synthase activity can be classified as a fish Mo-enzyme has been poorly demonstrated.

Method for assessing the content of molybdenum enzymes in the internal organs of fish.

Molybdenum enzymes (Mo-enzymes) contain a molybdenum cofactor (MoCo) in the active site. These enzymes are potentially interesting for studying the survival mechanism of fish under hypoxic water conditions. This is because Mo-enzymes can synthesize nitric oxide from nitrates and nitrites, which are present in high concentrations under hypoxic water conditions.