Copper is mainly transported by -

Ans. is 'a' i.e., Ceruloplasmin Copper is mainly transported as ceruloplasmino Normally, 40% to 60% of daily ingested copper (2 to 5 mg) is absorbed in the stomach & duodenum,o It is transported to the liver loosely complexed with albumin.o Free copper dissociates and is taken up into hepatocytes, where it is incorporated into an oy-globulin synthesized in the endoplasmic reticulum to form ceruloplasmin (a copper-containing metallothionein) and resecretedinto plasma.o Ceruloplasmin accounts for 90% to 95% of plasma copper, although its biologic role is unknown, since the six to seven atoms of copper in each protein molecule are not readily exchangeable,o Circulating ceruloplasmin is desialylated as part of normal plasma protein agingo Desialylated ceruloplasmin is endocvtosed by the liver, degraded within tysosomes, and its copper is excreted into bile. This degradation,#'excretion pathway is the primary route for copper elimination,o Estimated total body copper is only 50 to 150 mg.