Cystein, cystin

Alanine. Transamination of alanine forms pyruvate. Perhaps for the reason advanced under glutamate and aspartate catabolism, there is no known metabolic defect of alanine catabolism. Cysteine. Cystine is first reduced to cysteine by cystine reductase (Figure 30-7). Two different pathways then convert cysteine to pyruvate (Figure 30-8). 

Vandeberg, P. J. and Johnson, D. C., Pulsed electrochemical detection of cysteine, cystine, methionine, and glutathione at gold electrodes following their separation by liquid chromatography, Anal. Chem., 65, 2713, 1993. 

Tonzetich J, Carpenter PAW. 1971. Production of volatile sulphur compounds from cysteine, cystine and methionine by human dental plaque. Arch Oral Biol 16 599-607. 

Determination of iodo amino acids by HPLC with inductively coupled plasma (ICP)-MS detection had LOD 35-130 pg of I, which is about one order of magnitude lower than with UVD usually applied for these compounds175. Amino acids and peptides containing sulfur, such as cysteine, cystine, methionine and glutathione, can be determined after HPLC separation by pulsed electrochemical detection, using gold electrodes176. 

L-Amino acids, 2.5 X 10+6 molar solution of alanine, arginine, asparagine, aspartic acid, cysteine, cystine, glutamine, glutamic acid, glycine, histidine, hydroxyproline, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, valine. 

SULFUR (In Biological Systems). Sulfur, in some form, is required by all living organisms. It is utilized in various oxidation stales, including sulfide, elemental sulfur, sulfite, sulfate, and thiosulfate by lower forms and in organic combinations by all. The more important sulfur-containing organic compounds include the amino acids (cysteine, cystine, and methionine, which are components of proteins) the vitamins thiamine and... 

Cysteine, cystine, tryptophan, tyrosine and the peptide bond are capable of reducing Cu to Cu, but... 

Cysteine + Cystine Albumin Added, Cystine, Recovered i... 

Thiophenes are extremely important in flavor and are responsible for the mild sulfurous odor of cooked meat. Numerous other thiophenes have been identified during heating of meat or meat constituents. The sulfur in thiophene may be derived from amino acids (cysteine, cystine, methionine) or from vitamin. ... 

Further evidence of the importance of the Halliard reaction in the formation of volatile flavorants from meat precursors is gleaned by examining ingredients in reaction mixtures patented as synthetic meat constituents. Ching (31), examined 128 patents of meat flavor and found that 55 specified use of both amino acids and sugars. Cysteine, cystine, and glutamic acid were used in 39 such mixtures. Over 80 patents describe meat flavor "reaction products" (32). 

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