Biochemical Study of Myeloperoxidase in Blood and it's Relation to Atherosclerosis

Abstract

The research included studying of myeloperoxidase in human serum, The normal value of myeloperoxidase activity was found (27.71±0.74 U/ml) in control group for both sexes at (19-70 year), with no sex difference, while it was affected by age and smoking. The study also showed a significant increase in myeloperoxidase activity (38.95±1.01 U/ml) in serum of atherosclerosis patients group for both sexes at (31-80 year) in comparison with control, on the other hand, myeloperoxidase activity in serum of patients group was affected by sex, age, smoking and the intake of statins. The results also indicated a significant increase in the concenteration of total cholesterol, low density lipoprotein -cholesterol, C-reactive protein and troponin. While a significant decrease in high density lipoprotein -cholesterol, total protein, albumin, globulin, chloride and arylesterease in serum of patients group in comparison with control. Correlation study was performed between the measured biochemical parameters and myeloperoxidase activity in serum by linear correlation coefficient, The results also showed that there was a significant positive correlation between myeloperoxidase activity and troponin in atherosclerosis patients. Also, the research included the isolation of myeloperoxidase from normal human serum using different biochemical techniques, including: precipitation by ammonium sulfate, dialysis, gel filtration chromatography on sephadex G-100. The results predicted that spicefic activity and the number of fold of purification were (8.865 U/ml) and (25) respectively for partially purified enzyme. Furthermore, the comparative molecular weight of the partially isolated myeloperoxidase was (151±1.8 kDa) using gel filtration chromatography. The results were predicted also that myeloperoxidase containing heam group, zinc and calcium elements, which indicated that the enzyme is glycoproteins type. The study showed that the optimum conditions of myeloperoxidase were obtained at the first minute using sodium citrate (0.1 M) as buffer at pH (5.0), at a temperature (45 ºC) and (12 mM) of ο-dianisidin as substrate. It was found that Vmax and Km have the values of (24.27 U/ml) and (2.443 mM) respectively. Ethylene diamine tetraacetic acid, sodium azide, 2-mercaptoethanol and sodium chloride showed inhibition on the activity of myeloperoxidase, where sodium azide had more inhibition in the activity and in an irreversible non competitive inhibition type.