Background: The purpose of this study was to evaluate α-amylase inhibitory effects hydroethanolic extracts bark from Daniella oliveri, Sclerocarya birrea, Maranthes polyandra, and Pteleopsis suberosa fight type-II diabetes. Methods: Compound extractions were performed by hydroethanol maceration followed liquid-liquid fractionation with solvents. TLC profiling carried out different fractions. pl...

Different inhibition types of the saturation kinetics involving a synthesized model complex, [Bu4N]3[MoVIO2(mnt)2] (E) (where mnt2- = 1,2-dicyanoethylenedithiolate), and HSO3- as the substrate (S) by structurally similar anions SO4(2-), H2PO4- and H2PO3- have been shown for the first time in relevance to the reductive half reaction of the native enzyme sulphite oxidase. SO4(2-) acts as a compet...

The catalytic oxidation of catechol by crude preparations of mushroom tyrosinase was studied by a method yielding data on initial reaction velocities. Graphical analysis of the results suggests that an excess of catechol inhibits its own oxidation by a competitive process, thus accounting for the observed optimum in the substrate concentration. However, added phenol, though itself a substrate, ...

Memory retrieval is often challenged by other irrelevant competing memories that cause interference. This phenomenon is typically studied with the retrieval practice paradigm in which a category cue (e.g., Fruits) is presented together with an item-specific cue (e.g., Or::). Presentation of the category cue usually induces interference by reactivating competing memories (e.g., Banana, Apple, et...

objective(s):involvement of tyrosinase in the synthesis of melanin and cell signaling pathway has made it an attractive target in the search for therapeutic inhibitors for treatment of different skin hyperpigmentation disorders and melanoma cancers. materials and methods: in the present study, we conducted a comprehensive kinetic analysis to understand the mechanisms of inhibition imposed by 2-...

In the present study, we investigated if priming of autoreactive CD8(+) T cells would be inhibited by competitive peptides for major histocompatibility complex (MHC) class I binding. We used a mouse model of vitiligo which is induced by immunization of K(b)-binding tyrosinase-related protein 2 (TRP2)-180 peptide. Competitive peptides for K(b) binding inhibited IFN-γ production and proliferation...

There are a variety of methods available to calculate the inhibition constant (Ki) that characterizes substrate inhibition by a competitive inhibitor. Linearized versions of the Michaelis-Menten equation (e.g., Lineweaver-Burk, Dixon, etc.) are frequently used, but they often produce substantial errors in parameter estimation. This study was conducted to compare three methods of analysis for th...

Models of spatial attention are often based on the concept of a salience map. In computational cognitive neuroscience, such maps are implemented as a collection of nodes with self-excitation and lateral inhibition between all nodes (competitive interaction map). Here, we test some critical predictions of this idea. We argued that task demands, more precisely the level of attention required, can...

PURPOSE Telaprevir inhibits CYP3A resulting in drug-drug interactions (DDI) of unprecedented magnitude. We investigated the mechanisms by which telaprevir inhibits the oxidation of midazolam and tacrolimus in human liver microsomes (HLM). METHODS We performed a static mechanistic DDI prediction to evaluate whether previously reported competitive inhibition of CYP3A by telaprevir and its diast...

background tyrosinase is a copper-containing enzyme, which is widely distributed in microorganisms, animals and plants. it is also a key enzyme in melanin biosynthesis, which plays a crucial role in determining the color of mammalian skin and hair. in addition, unfavorable enzymatic browning of plant-derived foods by tyrosinase causes a decrease in nutritional quality and economic loss of food ...