The influence of micelle formation on lipoxygenase kinetics

The effects of a series of n-alcohols and n-carboxylic acids on lipoxygenase activity was studied. It was shown that to a large extent the effects of these compounds could be ascribed to physiochemical interaction with the substrate solution rather than a direct action on the enzyme itself. The effect of better substrate analogues such as stearate and oleate could also be ascribed to this effect. A type-2 lipoxygenase was found to have a very unusual velocity-substrate relationship which could be normalized by addition of calcium chloride in amounts stoichiometric with the substrate. An excess of calcium inhibited the enzyme. By comparison of results with linoleoyl sulphate/linoleoyl alcohol mixed micelles, an explanation for this unusual velocity-substrate activity is presented.