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 oxide etching with condensed plasma reaction product

Abstract: Oxide material, on a substrate, in a reactor, is etched by dissolving a hydrogen halide reaction product in a liquid phase reaction product. Both the hydrogen halide and liquid phase reaction products are produced through a chemical reaction of a reactive gas containing hydrogen and halogen elements as well as at least one gaseous compound which has been remotely activated. The liquid phase reaction product is obtained by condensation on the oxide material. The use of charged particle beams and irradiating light is discussed.

Method for producing high quality thin layer films on substrates

Abstract: A method for producing high quality, thin layer films of inorganic compounds upon the surface of a substrate is disclosed The method involves condensing a mixture of preselected molecular precursors on the surface of a substrate and subsequently inducing the formation of reactive species using high energy photon or charged particle irradiation The reactive species react with one another to produce a film of the desired compound upon the surface of the substrate

What Factors Influence the Rate Constant of Substrate Epoxidation by Compound I of Cytochrome P450 and Analogous Iron(IV)-Oxo Oxidants?

Abstract: The cytochromes P450 are a versatile range of mono-oxygenase enzymes that catalyze a variety of different chemical reactions, of which the key reactions include aliphatic hydroxylation and C═C double bond epoxidation. To establish the fundamental factors that govern substrate epoxidation by these enzymes we have done a systematic density functional theory study on substrate epoxidation by the active species of P450 enzymes, namely the iron(IV)-oxo porphyrin cation radical oxidant or Compound I. We show here, for the first time, that the rate constant of substrate epoxidation, and hence the activation energy, correlates with the ionization potential of the substrate as well as with intrinsic electronic properties of the active oxidant such as the polarizability volume. To explain these findings we present an electron-transfer model for the reaction mechanism that explains the factors that determine the barrier heights and developed a valence bond (VB) curve crossing mechanism to rationalize the observed tr...

Apatite coated on organic polymers by biomimetic process: improvement in its adhesion to substrate by glow-discharge treatment.

Abstract: A dense, uniform, and highly biologically active bone-like apatite layer can be formed in arbitrary thickness on any kind and shape of solid substrate surface by the following biomimetic method at ordinary temperature and pressure: First, a substrate is set in contact with particles of bioactive CaOSiO2-based glass soaked in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma so that a number of apatite nuclei are formed on the substrate. Second, the substrate is soaked in another solution with ion concentrations 1.5 times those of SBF (1.5SBF) so that the apatite nuclei grow in situ. In the present study, organic polymer substrates were treated with glow-discharge in O2 gas atmosphere, then subjected to the above-mentioned biomimetic process. The induction periods for the apatite nucleation on all the examined organic polymers were reduced from 24 to 6 h, with glow-discharge treatment. The adhesive strengths of the formed apatite layer to the substrates increased from about 4 to 10 MPa for poly(ethylene terephthalate) and poly-ether sulfone, and from 1 ∼ 2 to 6 ∼ 7 MPa even for poly(methyl methacrylate), polyamide 6 and polyethylene. It is supposed that highly polar groups such as carbonyl, ester, hydroxyl, and carboxyl ones formed by glow-discharge treatment increased the affinity of a silicate ion with the substrates to decrease the induction period, and also increased the affinity of the apatite with the substrate to increase the adhesive strength. The apatite-organic polymer composites thus obtained are expected to be useful as bone-repairing materials as well as soft tissue-repairing materials. © 1995 John Wiley & Sons, Inc.

Histochemical demonstration of a species-specific trypsin-like enzyme in mast cells.

Abstract: DURING the investigation of a new histochemical substrate, Nα-benzoyl-dl-arginine-β-naphthylamide liydrochloride, localization by a simultaneous azo coupling reaction of enzymatic activity to mast cells in human and dog tissues was noted. Recently, Benditt has described the presence of an enzyme in the mast cells of numerous species resembling bovine α-chymotrypsin. This enzyme hydrolyses the histochemical substrate 3-chloroacetyl-2-naphthoic acid anilide1. Although Nα-benzoyl-dl-arginine-β-naphthylamide hydrochloride has been shown in biochemical systems to be a substrate for trypsin and not for α-chymotrypsin, carboxypeptidase, liver esterase or ‘leucine’ aminopeptidase2, it was thought of importance to attempt to define as closely as possible the characteristics of the enzyme in mast cells hydrolysing Nαa - benzoyl - dl - arginine - β - naphthylamide hydrochloride and to differentiate it from other known mast cell enzymes.