The Alteration of Some Aromatic Amino Acids and Polyhydric Phenols by Clay Minerals

Thomas D. Thompson and Atsuma Tsunashina*
Georgia Kaolin Company, 1185 Mary Street, Elizabeth, New Jersey 07207, U.S.A.
* Department of Chemical Engineering, University of Hokkaidō, Sapporo Hokkaidō, Japan

Abstract: These studies concern the catalytic activity of clays on amino acids, particularly tyrosine. Polyhydric phenols were included to help understand the tyrosine reactions.

Below pH 3, tyrosine is adsorbed on clay minerals by cation exchange. Above pH 3, oxidative degradation of tyrosine occurs, the L-isomer altering more rapidly. The rate of alteration depends upon the particular clay mineral, surface modifications such as polyphosphate treatment, heating, and the presence of copper, aluminium, and mercury. A free radical mechanism is proposed for the alteration.

Clays and Clay Minerals; October 1973 v. 21; no. 5; p. 351-361; DOI: 10.1346/CCMN.1973.0210511
© 1973, The Clay Minerals Society
Clay Minerals Society (www.clays.org)