Sodium triacetoxyborohydride is presented as a general reducing agent for the reductive amination of aldehydes and ketones. Procedures for using this mild and selective reagent have been developed for a wide variety of substrates. The scope of the reaction includes aliphatic acyclic and cyclic ketones, aliphatic and aromatic aldehydes, and primary and secondary amines including a variety of wea...

Two methods were used for the quantitation of S-adenosylmethionine decarboxylase protein. The first involved titrating the active site of the enzyme by reduction of the Schiff base between 3H-decarboxylated S-adenosylmethionine and the pyruvate prosthetic group with sodium cyanoborohydride. The second method was radioimmunoassay with rabbit antiserum which was used to determine the total immuno...

Vanillyl alcohol oxidase (VAO) from Penicillium simplicissimum is a covalent flavoprotein that has emerged as a promising biocatalyst for the production of aromatic fine chemicals such as vanillin, coniferyl alcohol and enantiopure 1-(4’-hydroxyphenyl) alcohols. The largescale production of this eukaryotic enzyme in Escherichia coli has remained challenging thus far. For that reason an alternat...

Lactose has been coupled to the lysine residues of the cross-linked dimer of bovine pancreatic ribonuclease A by reductive amination with cyanoborohydride. Derivatives of ribonuclease dimer that contained up to 10 Nepsilon-1-(1-deoxylactitolyl)-lysine residues per molecule had greater than 75% of the enzymic activity of the unmodified enzyme toward yeast RNA. Upon intravenous injection of the 1...

The flavin-dependent enzyme 2-haloacrylate hydratase (2-HAH) catalyzes the conversion of 2-chloroacrylate, a major component in the manufacture of acrylic polymers, to pyruvate. The enzyme was expressed in Escherichia coli, purified, and characterized. 2-HAH was shown to be monomeric in solution and contained a non-covalent, yet tightly bound, flavin adenine dinucleotide (FAD). Although the cat...

Ca2+ and GTP are the main modulators of type-2 transglutaminases. To study the interaction of the enzyme with GTP, we have employed periodate-oxidized GTP as an affinity-label probe. Dialdehyde GTP bound irreversibly to type-2 transglutaminase in a time-dependent way with 1:1 stoichiometry at complete modification. The reaction took place in the absence, but was more rapid in the presence, of c...

General Procedures. All reactions were carried out under an inert nitrogen atmosphere unless otherwise stated. All reagents were purchased at the highest commercial quality and used as received unless otherwise stated. Dry methanol (MeOH), dichloromethane (CH2Cl2), benzene, toluene (PhMe), triethylamine (Et3N), and tetrahydrofuran (THF) were obtained by passing these previously degassed solvent...

conclusions diclofenac-loaded nanoparticles based on properties of chitosan gelation could delay the release of drugs in the stomach and be further evaluated for the enteric delivery of diclofenac. objectives the aim of this study was to prepare and evaluate diclofenac-loaded chitosan nanoparticles based on the ionotropic gelation method. materials and methods chitosan (cs) nanoparticles contai...

BACKGROUND Alcohol consumption is one of the top 10 risks for the worldwide burden of disease and an established cause of head and neck cancer, as well as cancer at other sites. Acetaldehyde, the major metabolite of ethanol, reacts with DNA to produce adducts, which are critical in the carcinogenic process and can serve as biomarkers of exposure and, possibly, of disease risk. Acetaldehyde asso...