Myeloperoxidase, a heme enzyme secreted by activated phagocytes, uses H(2)O(2) and Cl(-) to generate the chlorinating intermediate hypochlorous acid (HOCl). This potent cytotoxic oxidant plays a critical role in host defenses against invading pathogens. In this study, we explore the possibility that myeloperoxidase-derived HOCl might oxidize nucleic acids. When we exposed 2'-deoxycytidine to th...

Fucoxanthin is a natural carotenoid obtained from seaweed which exhibits antioxidant properties. This research aimed to assess whether fucoxanthin, immobilized on aluminum-silicon carrier particles, has toxic effect immune cells. The viability, proliferation, nitric oxide production and myeloperoxidase activity of thymocytes splenocytes mice in vitro were studied. It was shown that increased th...

Scavenging of the vasodilator nitric oxide by myeloperoxidase activity in the vasculature may contribute to hypertension. Because hydrogen peroxide is a cosubstrate of myeloperoxidase, hyperglycemia-induced oxidative stress may strengthen the relationship between myeloperoxidase and blood pressure. We investigated this relationship and its modification by hyperglycemia and oxidative stress in a...

Partial amino acid sequence of human myeloperoxidase was determined, and a 41-base oligonucleotide containing deoxyinosines at four positions was chemically synthesized. By using the oligonucleotide as a probe, cDNA clones for human myeloperoxidase were isolated from a cDNA library constructed with mRNA from human promyelocytic leukemia HL-60 cells. One of the clones containing a 2.6-kilobase i...

Appropriately stimulated neutrophils release peroxidase and undergo a respiratory burst to form hydrogen peroxide (H2O2) and hydroxyl radicals (OH). We report here that both the myeloperoxidase-H2O2-halide system and OH released in this way can degrade the leukotrienes (LT) formed by neutrophils. More LTB4 and LTC4 were recovered from the supernatants of chronic granulomatous disease neutrophil...

Myeloperoxidase. H,O,, and a halide form a potent antimicrobial system which is operative in the polymorphonuclear leukocyte (PMN). The formation of singlet oxygen (‘0,) by this system is suggested by (a) the conversion of 2,5diphenylfuran to its specific singlet oxygen product cisdibenzoylethylene (cis-DBE); (b) the inhibition of this reaction by the ‘0, quenchers p-carotene, bilirubin, histid...