fumaramide and fumaric-acid

A series of fumarate analogues has been used to explore the molecular mechanism of the activation of dopamine beta-mono-oxygenase by fumarate. Mesaconic acid (MA) and trans -glutaconic acid (TGA) both activate the enzyme at low concentrations, similar to fumarate. However, unlike fumarate, TGA and MA interact effectively with the oxidized enzyme to inhibit it at concentrations of 1-5 mM. Monoethylfumarate (EFum) does not activate the enzyme, but inhibits it. In contrast with TGA and MA, however, EFum inhibits the enzyme by interacting with the reduced form. The saturated dicarboxylic acid analogues, the geometric isomer and the diamide of fumaric acid do not either activate or inhibit the enzyme. The phenylethylamine-fumarate conjugate, N -(2-phenylethyl)fumaramide (PEA-Fum), is an approximately 600-fold more potent inhibitor than EFum and behaves as a bi-substrate inhibitor for the reduced enzyme. The amide of PEA-Fum behaves similarly, but with an inhibition potency approximately 20-fold less than that of PEA-Fum. The phenylethylamine conjugates of saturated or geometric isomers of fumarate do not inhibit the enzyme. Based on these findings and on steady-state kinetic analysis, an electrostatic model involving an interaction between the amine group of the enzyme-bound substrate and a carboxylate group of fumarate is proposed to account for enzyme activation by fumarate. Furthermore, in light of the recently proposed model for the similar copper enzyme, peptidylglycine alpha-hydroxylating mono-oxygenase, the above electrostatic model suggests that fumarate may also play a role in efficient electron transfer between the active-site copper centres of dopamine beta-mono-oxygenase.

Topics: Amides; Animals; Ascorbic Acid; Binding Sites; Cattle; Dopamine beta-Hydroxylase; Dose-Response Relationship, Drug; Electron Transport; Enzyme Activation; Fumarates; Glutarates; Kinetics; Maleates; Models, Chemical; Models, Molecular; Oxygen; Phenethylamines; Spectrophotometry; Tyramine

A novel poly(ether urethane amide) was synthesized by chain-extending the prepolymer with fumaric acid, resulting in a polymer exhibiting superior mechanical properties and containing chemically active derivatization sites, stemming from the fumaramide double bond. The derivatization of the active sites was performed via a Michael-like addition of amine-terminated poly(ethylene oxide) chains, which when performed in bulk, greatly affected the mechanical properties of the polymer, except in the case in which a relatively high molecular weight was grafted. Surface grafting of the polymer led to a significantly lower effect on its mechanical properties, which was minimal when a high molecular weight molecule was used.

Topics: Absorption; Amides; Cross-Linking Reagents; Fumarates; Molecular Weight; Polyethylene Glycols; Polyurethanes; Spectroscopy, Fourier Transform Infrared; Thermography