[Show abstract][Hide abstract] ABSTRACT: We described a spectrophotometric method for measuring hemoglobin peroxidase activity in human plasma using o-dianisidine (o-DA) as the substrate and myeloperoxidase specific inhibitor 4-aminobensoic acid hydrazide (ruling out the probable contribution of myeloperoxidase to the measured parameter value). The optimal conditions (pH 5.5; 2 mM H2O2) have been determined, at which hemoglobin makes the main contribution to plasma oxidation of o-DA. A significant positive correlation between hemoglobin peroxidase activity measured by the spectrophotometric method and hemoglobin level measured by the pyridine hemochromogenic method has been detected (r=0.624; p<0.01) in plasma specimens from 16 donors. Plasma hemoglobin peroxidase activities were measured in healthy individuals and patients with type 2 diabetes mellitus and coronary heart disease. High plasma hemoglobin peroxidase activities in both groups of patients indicates disorders in the mechanisms of clearance of hemoglobin and its highly reactive derivatives and can serve as specific markers of diseases associated with oxidative stress.
Full-text · Article · Apr 2013 · Bulletin of Experimental Biology and Medicine
[Show abstract][Hide abstract] ABSTRACT: We performed a comparative analysis of functional activity of neutrophils in patients with type 2 diabetes mellitus with and without symptoms of CHD. Enhanced H2O2 production by neutrophils in response to N-formyl-Met-Leu-Phe (fMLP) was found in patients with type 2 diabetes mellitus. In patients with type 2 diabetes mellitus associated with CHD, fMLP-induced release of myeloperoxidase from azurophilic granules of neutrophils was reduced and plasma myeloperoxidase level was elevated. Increased peroxidase activity of myeloperoxidase, reduced plasma catalase activity, and increased levels of TBA-reactive lipid peroxidation products and oxidized glutathione were detected in patients of both groups. Since myeloperoxidase is an important neutrophilic mediator of oxidative stress, its increased activity in the blood can be an additional marker of oxidative stress and cardiovascular risk in patients with diabetes mellitus.
Full-text · Article · Oct 2012 · Bulletin of Experimental Biology and Medicine
[Show abstract][Hide abstract] ABSTRACT: Using a previously developed spectrophotometric method (Bioorg. Khim. 2009, vol. 35, pp. 629–639) a significant increase of
myeloperoxidase (MPO) activity (versus healthy control) was found in blood plasma of patients with type 2 diabetes mellitus
(DM2) without cardiovascular complications, and also in patients with ischemic heart disease (IHD). The plasma MPO concentration
measured by an enzyme-linked immunosorbent assay was significantly higher only in blood plasma of patients with DM2 and IHD.
A significant positive correlation between blood MPO activity and blood MPO content was observed only in blood plasma samples
from healthy donors. Increased MPO activity did not correlate with MPO concentration in blood plasma of patients with DM2
and DM2 with IHD. Taken together, these results indicate that studies on the MPO role in the development of pathological processes
should include simultaneous determination of both the amount of enzyme and its peroxidase activity in blood of patients. The
proposed approach gives comprehensive information about the relationship between MPO activity and MPO concentration in patient’s
blood. Since the high concentration of MPO is a diagnostically important parameter for the prediction of development of endothelial
dysfunction and cardiovascular diseases, the obtained results point to the contribution of MPO-dependent reactions in cardiovascular
complications associated with diabetes mellitus. MPO activity may serve as an additional diagnostic criterion for determination
of risk of IHD in DM patients.
Keywordsmyeloperoxidase–diabetes mellitus–neutrophils–peroxidase activity–blood plasma–enzyme-linked immunosorbent assay
Full-text · Article · Sep 2011 · Biochemistry (Moscow) Supplement Series B Biomedical Chemistry