S- 2-aminoethyl cysteine

L-2-AminQ-3 (2-aininoethylthio) propanoic acid [S-(2-aminoethyl)cysteine]... 

S., Simultaneous determination of urinary cystathionine, lanthionine, S-(2-aminoethyl)-L-cysteine and their cyclic compounds using liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization, /. Chromatogr. B, 698, 301, 1997. 

Lugli, J. Gaziola, S.A. Azevedo, R.A. Effects of calcium, S-adenosylmethio-nine, S-(2-aminoethyl)-L-cysteine, methionine, valine and salt concentration on rice aspartate kinase isoenzymes. Plant Sci., 150, 51-58 (2000)... 

S-(2-Aminoethyl)-L-cysteine (AEC), H2N-CH2-CH2-S-CH2-CH(NH2)-COOH, a lysine analog, acts as a false feedback inhibitor on aspartokinase, which produces aspartylphosphate from aspartate. The inhibitor simulates, for aspartokinase, the absence of lysine and threonine, and as a consequence the AEC insensitive mutant is no longer inhibited by lysine and threonine. The result was a yield increase from 0 to 16 g L 1. 

Sano K, Shiio I. (1970). Microbial production of L-lysine 111. Production by mutants resistant to S-(2-aminoethyl)-L-cysteine. J Gen Appl Microbiol, 16, 373-391. 

The cells could produce even more lysine if the kinase were to remain active but insensitive to a high lysine concentration. Mutants of the homoserine auxotrophs of C. glutamicum were isolated with this property by growing the organism in the presence of toxic isosteres (close structural analogues) of lysine (e.g. S-(2-aminoethyl)-L-cysteine). One way in which the cells can become resistant to the toxic isostere is to overproduce lysine. This is likely to occur in cells where the mutation alters aspartyl kinase in such a way as to make it insensitive to inhibition by lysine, while allowing it to retain its full catalytic activity. 

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