Human cystathionine β-synthase (CBS), a novel heme-containing pyridoxal 5'-phosphate enzyme, catalyzes the condensation of homocysteine and serine or cysteine to produce cystathionine and H(2)O or H(2)S, respectively. The presence of heme in CBS has limited spectrophotometric characterization of reaction intermediates by masking the absorption of the pyridoxal 5'-phosphate cofactor. In this stu...

Glutathione is an important thiol-containing compound involved in the detoxification process in erythrocytes. Its thiol group reacts with a variety of xenobiotics in a glutathione S-transferase catalyzed reaction to form conjugates that are effluxed from the erythrocytes by an ATP dependent transport mechanism. A well studied experimental system is the transport of the conjugate of glutathione ...

Alternate strategies for prevention of enzymatic browning of fruits and vegetables are required by food industries due to restrictions and several negative health attributes of sulphites, which are effective inhibitors of enzymatic browning reaction. These reactions result mostly from polyphenol oxidase (PPO). The present study was conducted to evaluate the antioxidant and PPO inhibitory potent...

S-Nitrosothiols or thionitrites with the general formula RSNO are formally composed of the nitrosyl cation (NO+) and a thiolate (RS-), the base of the corresponding acids RSH. The smallest S-nitrosothiol is HSNO and derives from hydrogen sulfide (HSH, H2S). The most common physiological S-nitrosothiols are derived from the amino acid L-cysteine (CysSH). Thus, the simplest S-nitrosothiol is S-ni...

An aged Ru complex has been successfully employed for the photochemical monoreduction of NAD + achieving mediator-free NADH formation with only aid l -cysteine and visible light.

Methylmercury (MeHg) readily crosses cell membrane barriers to reach its target tissue, the brain. Although it is generally assumed that this rapid transport is due to simple diffusion, recent studies have demonstrated that MeHg is transported as a hydrophilic complex, and possibly as an L-cysteine complex on the ubiquitous L-type large neutral amino acid transporters (LATs). To test this hypot...

A mutant designated as pvcys exhibiting huge deficiency in foliar L-cysteine desulfhydrase and D-cysteine desulfhydrase activity were isolated from an ethylmethane sulfonate-mutagenized M2 population of a Phaseolus vulgaris L. genotype VL 63. The mutant showed growth inhibition and morpho-agronomic anomalies but exhibited high cysteine content and very low endogenous hydrogen sulfide concentrat...

Excitatory amino acid transporters (EAATs) limit glutamatergic signaling and maintain extracellular glutamate concentrations below neurotoxic levels. Of the five known EAAT isoforms (EAATs 1-5), only the neuronal isoform, EAAT3 (EAAC1), can efficiently transport the uncharged amino acid L-cysteine. EAAT3-mediated cysteine transport has been proposed to be a primary mechanism used by neurons to ...

INTRODUCTION Helicobacter-induced atrophic gastritis with a hypochlorhydric milieu is a risk factor for gastric cancer. Microbes colonising acid-free stomach oxidise ethanol to acetaldehyde, a recognised group 1 carcinogen. OBJECTIVE To assess gastric production of acetaldehyde and its inert condensation product, non-toxic 2-methyl-1,3-thiazolidine-4-carboxylic acid (MTCA), after alcohol inta...