Disease relevance of Cysteinyl-S-sulfonic acid

• Sulfite oxidase deficiency is characterized by severe neurologic dysfunction, dislocation of the lenses, and the accumulation and excretion of inorganic sulfite, thiosulfate, and S-sulfocysteine [1].
• Enzymatic proof for the identity of the S-sulfocysteine synthase and cysteine synthase B of Salmonella typhimurium [2].
• O-Acetylserine sulfhydrylase and S-sulfocysteine synthase activities of Rhodospirillum tenue [3].
• Forteen species (17 strains) of phototrophic bacteria as well as one strain of Thiobacillus denitrificans were tested for cysteine synthase and S-sulfocysteine synthase [4].

High impact information on Cysteinyl-S-sulfonic acid

• Remarkably, GSTB1-1ox and GSTB1-1red are equally able to catalyze a glutaredoxin-like catalysis using cysteine S-sulfate and hydroxyethyl disulfide as substrates [5].
• Cysteine-S-sulfate: brain damaging metabolite in sulfite oxidase deficiency [6].
• Here we demonstrate that cysteine-S-sulfate induces the glutamate type of neuropathology in the rat central nervous system when administered subcutaneously to infants or intracerebrally to adults [6].
• GPX has a higher specificity constant for S-sulfocysteine than DHA, and both assay systems gave nearly identical specificity constants for GSH [7].
• Plots of thioltransferase activity as a function of S-sulfocysteine or hydroxyethyl disulfide concentration did not show normal Michaelis-Menten kinetics [8].

Chemical compound and disease context of Cysteinyl-S-sulfonic acid

• O-Acetylserine sulfhydrylase in cell-free extracts of Rhodospirillum tenue was markedly repressed after growth in the presence of sulfide or thiosulfate, whereas S-sulfocysteine synthase activity remained almost unchanged [3].

Biological context of Cysteinyl-S-sulfonic acid

• S-sulphocysteine being destroyed during acidic hydrolysis was identified after enzymic hyrolysis of dialyzed and lyophilized filtrates [9].

Anatomical context of Cysteinyl-S-sulfonic acid

• Prenatal diagnosis by assay of sulfite oxidase in cultured amniotic fluid cells and by direct measurement of amniotic fluid S-sulfocysteine is possible [10].

Associations of Cysteinyl-S-sulfonic acid with other chemical compounds

• The catalytic activity of the released enzyme with S-sulfocysteine and glutathione as substrates had a distinct optimum pH at 7 [11].
• An HPLC assay for detection of elevated urinary S-sulphocysteine, a metabolic marker of sulphite oxidase deficiency [12].
• The purified enzyme appears to be homogeneous on sodium dodecyl sulfate (SDS)-gel electrophoresis and has a molecular weight (Mr) of 11,000, an isoelectric point (pI) of 8.1, and an optimum pH with S-sulfocysteine and GSH as substrates of 8 [13].
• Moreover, sulfite was produced that cleaved disulfide bonds of the substrate giving rise to S-sulfocysteine; soluble products of keratin degradation in the medium contained 2.1 to 6.5% of that substance [14].
• According to this hypothesis, the fungus excretes sulfite which cleaves the disulfide bonds of keratin to cysteine and S-sulfocysteine [15].

Gene context of Cysteinyl-S-sulfonic acid

• Cysteine S-sulfonate is, however, not reduced by cytosolic extracts in the presence of NADPH and would have to be eliminated from the cell by other means [16].

Analytical, diagnostic and therapeutic context of Cysteinyl-S-sulfonic acid

• Determination of S-sulfocysteine in urine by high-performance liquid chromatography [17].
• The procedure is based on precolumn derivatization of urinary amino acids with dimethylaminoazobenzene sulphonyl chloride (Dabsyl-Cl) and resolution of the modified S-sulphocysteine by reversed-phase HPLC [12].
• The incidental finding of hypouricemia led to a work-up for molybdenum cofactor (MoCo) deficiency; the diagnosis was confirmed by the altered urine chemistries, including elevated urine S-sulphocysteine [18].

References