Substrate (chemistry)

About: Substrate (chemistry) is a research topic. Over the lifetime, 35902 publications have been published within this topic receiving 740722 citations. The topic is also known as: enzyme substrate.

Method of film deposition using activated precursor gases

Abstract: A method for depositing a film on a substrate is provided. In one aspect, the method includes providing a metal-containing precursor to an activation zone, and activating the metal-containing precursor to form an activated precursor. The activated precursor gas is transported to a reaction chamber, and a film is deposited on the substrate using a cyclical deposition process, wherein the activated precursor gas and a reducing gas are alternately adsorbed on the substrate. Also provided is a method of depositing a film on a substrate using an activated reducing gas.

Manganese peroxidase from the basidiomycete Phanerochaete chrysosporium: spectral characterization of the oxidized states and the catalytic cycle.

Abstract: Manganese peroxidase (MnP), an extracellular heme enzyme from the lignin-degrading fungus Phanerochaete chrysosporium, catalyzes the Mn(II)-dependent oxidation of a variety of phenols. Herein, the authors spectroscopically characterize the oxidized states of MnP compounds I, II, and III and clarify the role of Mn in the catalytic cycle of the enzyme. Addition of 1 equiv of H/sub 2/O/sub 2/ to the native ferric enzyme yields compound I, characterized by absorption maxima at 407, 558, 605, and 650 nm. Addition of 2 or 250 equiv of H/sub 2/O/sub 2/ to the native enzyme yields compound II or III, respectively, identified by absorption maxima at 420, 528, and 555 nm or at 417, 545, and 579 nm, respectively. These characteristics are very similar to those of horseradish peroxidase (HRP) and lignin peroxidase (LiP) compounds I, II, and III. Addition of 1 equiv of either Mn(II), ferrocyanide, or a variety of phenols to MnP compound I rapidly reduces it to MnP compound II. In contrast, only Mn(II) or ferrocyanide, added at a concentration of 1 equiv, reduces compound II. The Mn(III) produced by the enzymic oxidation of Mn(II) oxidizes the terminal phenolic substrates. This indicates that compounds I and II of MnP contain 2more » and 1 oxidizing equiv, respectively, over the native ferric resting enzyme and that the catalytic cycle of the enzyme follows the path native enzyme ..-->.. compound I ..-->.. compound II ..-->.. native enzyme. In addition, these results indicate that Mn(II) serves as an obligatory substrate for MnP compound II, allowing the enzyme to complete its catalytic cycle. Finally, the Mn(II)/Mn(III) redox couple enables the enzyme to rapidly oxidize the terminal phenolic substrates.« less