Lecithin-cholesterol acyltransferase (LCAT) is a plasma enzyme which catalyzes the transacylation of the sn-2-fatty acid of lecithin to cholesterol, forming lysolecithin and cholesteryl ester. We have recently proposed a covalent catalytic mechanism for LCAT in which lecithin cleavage proceeds via the formation of a transition state tetrahedral adduct between the oxygen atom of the catalytic se...

The reaction between bis(2-benzothiazolyl)ketone and vinyl Grignard reagents bearing different substituents on the vinyl moiety gave the product derived from attack on the carbonylic carbon- and/or oxygen-atom. The regioselectivity of the attack depends on the kind of substituents bound to the vinylic carbon atoms and on their relative position. The reaction between vinylmagnesium bromide and 2...

Alkoxy (R1C(R2)(R3)O•) and Carbonyl (RC(•)O) radicals are important intermediates in the degradation chain of hydrocarbons. Both classes of radicals are subject to competing reaction chan-nels leading to different products which exhibit different ozone formation potentials: Alkoxy radicals (1) Reaction with O2 (kO2, => aldehyde/ketone + HO2); (2) thermal decomposition (kdis, => aldehyde/ketone ...

Hexaamminecobalt(II) bis-[tetra-carbonyl-cobaltate(-I)], [Co(NH3)6][Co(CO)4]2, was synthesized by reaction of liquid ammonia with Co2(CO)8. The Co(II) atom is coordinated by six ammine ligands. The resulting polyhedron, the hexa-amminecobalt(II) cation, exhibits point group symmetry -3. The Co(-I) atom is coordinated by four carbonyl ligands, leading to a tetra-carbonyl-cobaltate(-I) anion in t...

Previous studies of the physiology of an aromatic-deficient mutant strain of Neurospora crassa, Y7655a (1, 2), have led to the following conclusions: (a) The biosynthesis of the aromatic rings of phenylalanine, tyrosine, tryptophan and p-aminobenzoic acid proceeds in Neurospora as it does in Escherichia coli (3) via 5-dehydroshikimic acid and shikimic acid. (b) Protocatechuic acid, the major co...

catalytic and photocatalytic reactions of (2-chloroethyl) phenyl sulfide (2-ceps), a mimic of bis (2-chloroethyl)  sulfide (i.e. sulfur mustard) were studied on the surfaces of titanium oxide. tio2 nanoparticles (anatase, rutile and mixture of 80% anatase/20% rutile) along with bulk tio2 were tested as reactive sorbents for reaction of 2-ceps at room temperature (25±0.5°c). reactions were monit...

Hydrogen sulfide (H2S), a classic cytochrome c oxidase inhibitor, is also an in vitro oxidase substrate and an in vivo candidate hormonal ('gasotransmitter') species affecting sleep and hibernation. H2S, nitric oxide (NO) and carbon monoxide (CO) share some common features. All are low-molecular-mass physiological effectors and also oxidase inhibitors, capable of binding more than one enzyme si...

In the net reaction catalyzed by homogentisate oxidase of rat liver, two atoms of osygen are added to the double bond between carbon atoms 1 and 2 of homogentisate (2, 3) resulting in the formation of maleylacetoacetate (Fig. 1). The enzyme is located in the soluble phase of the liver cell; its activity is totally independent of the hydrogen and electron transport system. Its properties and mod...