Myeloperoxidase: New Roles for an Old Molecule

Abstract

Myeloperoxidase (MPO) is a member of the heme peroxidase-cyclooxygenase superfamily. It is abundantly expressed in neutrophils and monocytes. During inflam mation MPO is released from leukocytes and catalyzes the formation of several reactive species and tissue damage. In this article we present state of the art knowledge on the general properties, biosynthesis and processing and trafficking of MPO. The basic functions of MPO in inflammation and oxidative stress are discussed in detail. This article also summarizes the studies that investigated the relationship between MPO and cardiovascular disease. An overview of the assays for determination of MPO, the sample type and preanalytical procedures is given. Future studies are needed before this marker is introduced into routine clinical practice.

Hydrogen sulfide activation in hemeproteins: The sulfheme scenario

“…Lactoperoxidase (LPO) and myeloperoxidase (MPO) are two important heme-containing peroxidases involved in the immune defense system [55–58]. Both defend the system from invading microorganism by the bactericidal activities of the oxidized substrates [56, 59]. For example, MPO catalyzes the formation of hypochlorous acid (HOCl) from chloride species and H 2 O 2 , which has antimicrobial activity and kills other pathogens in humans [59].…”

“…Both defend the system from invading microorganism by the bactericidal activities of the oxidized substrates [56, 59]. For example, MPO catalyzes the formation of hypochlorous acid (HOCl) from chloride species and H 2 O 2 , which has antimicrobial activity and kills other pathogens in humans [59]. In the resting form, the heme groups of LPO and MPO are penta-coordinated with the iron in the high spin ferric state.…”

Effect of collection tube type and freeze–thaw cycles on myeloperoxidase concentrations in blood samples of acute coronary syndrome patients

“…15 The reason for increased MPO concentrations in heparin samples in the study conducted by Shih et al 15 may be due to the fact that heparin helps in stimulating release of MPO from leukocytes and activates neutrophils during blood coagulation. 5 Scheffer et al 16 reported that MPO concentrations remained comparatively constant in heparin samples, when stored on ice, while storage of samples at room temperature for 2 h resulted in four-fold increase in MPO concentrations in heparin samples 16 (means temperature can cause an increase in MPO concentrations in heparin tubes).…”

“…An increase in MPO concentrations may occur during the early stages of ACS, even prior to the evidence of myonecrosis, probably reflecting instability of atherosclerotic plaque. 5 Several studies have reported that MPO concentrations may provide prognostic information in ACS patients. [6][7][8] A few important studies have investigated the role of MPO for risk stratification of CAD.…”

Myeloperoxidase and Glutamate-Cysteine Ligase Polymorphisms in Type 2 Diabetes Mellitus: A Preliminary Study / Polimorfizmi Mijeloperoksidaze I Glutamat-Cistein Ligaze U Diabetes Mellitusu Tipa 2: Preliminarna Studija

“…It has been de tected that the amount of GSH is parallel with the expression of the GCLC gene, of which the expression re gulated at the transcriptional level comes first (16)(17)(18). On the other hand, effects of the -3506A/G ve -129C/T polymorphisms which occur independently at the promoter region of the GCLC gene have been investi gated in myo cardial infarction (MI) and it has been observed that -129C/T polymorphism is in creased in individuals who have MI with respect to those who do not (19,20). Thus, GCLC is an essential enzyme for the glutat hio ne mechanism, and further comprehensive studies are needed in order to understand the effects of alte rations in this gene.…”