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Binding of copper (II) and other metal ions by lysinoalanine and related compounds and its significance for food safety

Journal Article · · Journal of Agricultural and Food Chemistry; (USA)
DOI:https://doi.org/10.1021/jf00082a010· OSTI ID:5085851
;  [1]
  1. Agricultural Research Service, Albany, CA (USA)

Acid-base equilibrium constants for the five ionizable groups and metal ion (Ca{sup 2+}, Mn{sup 2+}, Fe{sup 2+}, Co{sup 2+}, Ni{sup 2+}, Cu{sup +}, Zn{sup 2+}, Cd{sup 2+}, Hg{sup 2+}) binding constants of N{epsilon}-(2-amino-2-carboxyethyl)-L-lysine (lysino-alanine, LAL) have been determined at 25{degree}C and 0.16 M ionic strength by potentiometric titration. Less extensive data are reported for the related compounds DL-2,3-diaminopropanoic acid (DAPA), 3-((2-phenylethyl)amino)-DL-alanine (PEAA), and L-lanthionine (LAN), three other unnatural amino acids also formed during food processing. These unnatural amino acids are sufficiently strong chelators to influence copper transport by histidine in vivo at plasma levels of 49 {mu}M LAL, 23 {mu}M DAPA, 243 {mu}M PEAA, and 511 {mu}M LAN. Relatively high concentration of these compounds are calculated to be necessary for competitive binding of essential zinc ions and inactivation of carboxypeptidase A and other enzymes. Possible mechanisms for kidney damage by these dehydroalanine-derived copper chelators are discussed.

OSTI ID:
5085851
Journal Information:
Journal of Agricultural and Food Chemistry; (USA), Journal Name: Journal of Agricultural and Food Chemistry; (USA) Vol. 36:4; ISSN JAFCA; ISSN 0021-8561
Country of Publication:
United States
Language:
English