L-Cysteine HCI

Scanlan R.A., Kayser S.G., Libbey L.M. and Morgan M.E. (1973) Identification of volatile compounds from heated L-cysteine HCI/d-glucose. J Agric. Food Chem. 21, 673-5. 

L-Tyrosine [60-18-4] M 181.2, m 290-295 (dec), [ajp -10.0 (5M HCI). Likely impurities are L-cysteine and the ammonium salt. Dissolved in dilute ammonia, then crystd by adding dilute acetic acid to pH 5. Also crystd from water or EtOH/water, and dried at room temperature under vacuum over P2O5. 

Elevated concentrations of plasma homocysteine (HCY) are related to an increased risk of cardiovascular disease, which exists in numerous forms in plasma, with the main form existing as a disulfide with itself, cysteine, or albumin. Therefore, the first step in the measurement involves treatment with a reducing agent, in this case dithiothreitol (DTT), to obtain HCY in its free form (Eq. 16.34). Some amino acids (e.g., L-cysteine and L-methionine) are present in human plasma at higher molar concentrations than HCY and may interfere with this assay. To avoid this possible interference, the highly selective enzymatic conversion of HCY to S-adenosyl-L-homocysteine (SAH), as shown in Eq. 16.34, is used. Both reactions (reduction and conjugation) are accomplished in 30 min at 34 °C. 

Cross-reactivity was study for similar molecules expected to be present in plasma. L-Cysteine (hydrochloride) and L-methionine at 5 and 4.5 mmol/L, respectively, were assayed in buffer. The observed polarization values correspond to HCY concentrations of 0.0 and 0.1 pmol/L, respectively. Thus, the antibody-binding reaction is sufficiently selective in the presence of these potential interferents. 

L-Cysteine, N-acetyl-. See Acetylcysteine Cysteine chlorhydrate. See Cysteine hydrochloride anhydrous Cysteine chlorhydrate monohydrate. See Cysteine hydrochloride monohydrate Cysteine disulfide. See L-Cystine Cysteine HCI (INCI). See Cysteine hydrochloride anhydrous Cysteine HCI monohydrate. See Cysteine hydrochloride monohydrate Cysteine hydrochloride L-Cysteine hydrochloride. See Cysteine hydrochloride anhydrous... 

Synonyms L-2-Amino-3-mercaptopropanoic acid monohydrochloride monohydrate Cysteine chlorhydrate monohydrate Cysteine HCI monohydrate L-Cysteine hydrochloride monohydrate L-Cysteine monohydrochloride monohydrate... 

Cocodimonium hydroxypropyl hydrolyzed collagen Cocodimonium hydroxypropyl hydrolyzed hair keratin Cocodimonium hydroxypropyl hydrolyzed keratin Cocodimonium hydroxypropyl hydrolyzed rice protein Cocodimonium hydroxypropyl hydrolyzed silk Cocodimonium hydroxypropyl hydrolyzed soy protein Cocodimonium hydroxypropyl hydrolyzed wheat protein Cocodimonium hydroxypropyl silk amino acids Coco-ethyidimonium ethosulfate Coco-hydroxysultaine Coco-morpholine oxide Coco/oleamidopropyl betaine Cocotrimonium chloride Cocoyl benzyl hydroxyethyl imidazolinium chloride Cocoyl hydrolyzed collagen Cocoyl hydrolyzed keratin Cocoyl hydrolyzed soy protein Cocoyl polyglyceryl-4 hydroxypropyl dihydroxyethylamine Com (Zea mays) oil Corn starch/acrylamide/sodium acrylate copolymer Cyclomethicone L-Cysteine L-Cystine DEA-lauraminopropionate DEA-oleth-3 phosphate DEA-oleth-10 phosphate Decarboxy carnosine HCI Decylamine oxide Decyl betaine Dibehenyidimonium chloride Dibehenyldimonium methosulfate Dibehenyl methylamine... 

C3H7NO2 C5H9NO4 Alanine glutamate C3H7NO2S L-Cysteine C3H7NO2S HCI... 

Cysteine hydrochloride anhydrous C3H7NO2S HCI H2O Cysteine hydrochloride monohydrate C3H7NO3 D-Serine DL-Serine L-Serine... 

Scheme 3 Two literature precedents of thiolactone-based two-step one-pot sequences (a) treatment of y-thiobutyrolactone with propiolic acid in basic aqueous medium generates the acrylic acid 4 and (b) methanolysis and S-aUcylation of l.HCI enables the synthesis of 5-alkylhomo-cysteine 5...

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