Oxygen metabolites have been implicated in the pathogenesis of various types of acute tissue injury. One biologic source of oxygen metabolites is the reaction catalyzed by the enzyme xanthine oxidase. Because we previously demonstrated that the substrates for xanthine oxidase (hypoxanthine and xanthine) are elevated in the plasma of critically il l patients, we questioned whether the enzyme its...

combined oxidase/peroxidase that does the cross-linking, the cuticle separates into distinct layers, resulting in translucent worms that often suffer from massive blisters and defective movement. The clue that the cross-linking enzyme (called Duox for Dual Oxidase) might exist came from studies of phagocyte NADPH-oxidase. The latter enzyme generates bursts of superoxide to effect killing of eng...

In this study, it was shown for the first time that l-amino acid oxidase of Pseudomonas sp. AIU813, renamed as l-amino acid oxidase/monooxygenase (l-AAO/MOG), exhibits l-lysine 2-monooxygenase as well as oxidase activity. l-Lysine oxidase activity of l-AAO/MOG was increased in a p-chloromercuribenzoate (p-CMB) concentration-dependent manner to a final level that was five fold higher than that o...

Homocysteine thiolactone, selenohomocysteine lactone, and homoserine lactone were found to be competitive, irreversible inhibitors of lysyl oxidase, with KI values of 21 6 3 mM, 8.3 6 2.2 mM, and 420 6 56 mM, respectively. The first order rate constants for inactivation (k2) of the enzyme varied over a much smaller range, ranging from 0.12 to 0.18 to 0.28 min for the Se-, thio-, and O-lactones,...

Homocysteine thiolactone, selenohomocysteine lactone, and homoserine lactone were found to be competitive, irreversible inhibitors of lysyl oxidase, with KI values of 21 +/- 3 microM, 8.3 +/- 2.2 microM, and 420 +/- 56 microM, respectively. The first order rate constants for inactivation (k2) of the enzyme varied over a much smaller range, ranging from 0.12 to 0.18 to 0.28 min-1 for the Se-, th...

The enzyme NADPH oxidase is regulated by phospholipase D in intact neutrophils and is activated by phosphatidic acid (PA) plus diacylglycerol (DG) in cell-free systems. We showed previously that cell-free NADPH oxidase activation by these lipids involves both protein kinase-dependent and -independent pathways. Here we demonstrate that only the protein kinase-independent pathway is operative in ...

An enzyme L-lysine-A-oxidase has been obtained from Trichoderma harzianum Rifai F-180. The analysis of serum from CBA mice immunized five times with native L-lysine-A-oxidase intravenously, at a dose of 35 U/kg, showed that the preparation had virtually no effect on the immune response to Tdependent antigen. L-lysine-A-oxidase at a dose of 35 U/kg administered twice intradermally has no effect ...

Urate oxidase, or uricase (EC 1.7.3.3), is a peroxisomal enzyme that catalyzes the oxidation of uric acid to allantoin in most mammals. In humans and certain other primates, however, the enzyme has been lost by some unknown mechanism. To identify the molecular basis for this loss, urate oxidase cDNA clones were isolated from pig, mouse, and baboon, and their DNA sequences were determined. The m...

Glucose oxidase has wide applications in the pharmaceutical, chemical, and food industries. Many recent studies have enhanced key properties of this enzyme using directed evolution, yet without being able to reveal why these mutations are actually beneficial. This work presents a synergistic combination of experimental and computational methods, indicating how mutations, even when distant from ...