Separation of Lipoxygenase and Estimation of its Level in Blood of Males with Cardiovascular Disease

The lipoxygenase (LOX) can influence the risk of cardiovascular disease (and diabetes) by virtue of its effect on lipid metabolism. Therefore, the present study deals with the separation and estimation of the level of LOX in blood of males with cardiovascular disease (only /or in addition to diabetes).
The enzyme was separated and purified from the blood-cells homogenate by precipitation (using 0-55% ammonium sulfate), dialysing against the buffer solution and then by applying ion exchange chromatography, when three bands were distinguished. The enzyme showed different specific activities in the elution of these bands and the highest activity was for the second band. Concerning the characterization of enzyme, it has been found that the optimum condition of the enzyme was at pH 8, 40oC and the enzyme has km=1.99 mM at 12mM of the substrate (linoleate) concentration.
The results showed that the incidence of cardiovascular disease and diabetes led to a significant increase in the level of LOX in both the blood-cells homogenate and the serum.
The study also focused on assessing the serum total cholesterol (TC), high density lipoproteincholesterol (HDL-C), glutathione (GSH) and malondialdehyde (MDA). The results indicated that there was a significant increase in the level of TC and MDA and there was a significant decrease in the level of HDL-C and GSH in addition to an increase in the ratio of TC/HDL-C.
On the basis of the results, it may be concluded that the LOX in blood cells has more than one isoenzyme with different activities. In addition, the high level of LOX is considered as a negative indicator that promotes cardiovascular disease and diabetes.