Cobalt, Copper and Molybdenum in the Nutrition of Animals and Plants

Oxidative cross-linking of immune complexes by human polymorphonuclear leukocytes.

“…Oxidation of tyrosine to a quinone by specific or nonspecific oxidases could also mediate cross-linking of proteins (17). This mechanism has been shown to be responsible for the hardening of the cuticle of insects and crustaceans before pupation or molting (45), and for the hardening of sea urchin egg membrane after fertilization (46). In the latter case, a peroxidase from cortical granules, in conjunction with H202, react to generate di-and tri-tyrosine linkages that may contribute to the process of hardening (47).…”

Studies on Copper Metabolism. XIII. Hepatolenticular Degeneration1

“…That copper may have such an effect is suggested by the cirrhosis of the liver which has been produced experimentally in rabbits by the administration of large amounts of copper (41) and the cirrhosis which has been described in sheep under natural conditions which are conducive to the retention of copper in the tissues (42,43). Furthermore, in this laboratory it was possible to damage the renal tubular epithelium of rats by the administration of excessive amounts of copper (44).…”

“…Others have reported a similar event. A disease, known as "Enzootic Jaundice," has been described in sheep in Australia (42,43) and has been produced experimentally (46). In this condition, for reasons which are not understood, the tissues retain excessive quantities of copper.…”

Oxidation of Proteins by Tyrosinase and Peroxidase

“…Insect tyrosinase is produced as an inactive protyrosiiiase which is activated by certain detergents (26). The biological functions of tyrosinase in either plants or animals are by no means completely understood (27). In plants it has been proposed, and denied, that tyrosinase may function as a terminal oxidase in cell respiration (28,29), although it apparently does not play this role in insects (30).…”