Transport and storage of metals

Abstract

Current understanding of the means by which the trace metals copper, iron, and zinc are transported and stored in the human body is reviewed. Although metal-related inherited metabolic diseases manifest themselves as deficiencies in metalloenzymes, these deficiencies in fact arise from disturbances in the absorption/rejection or transport or storage phases of the metal metabolism. The considerable information available on iron metabolism shows these phases to be closely interrelated with a number of feedback mechanisms operating as controls on the various metabolic stages. Copper and zinc have vastly different roles in their enzymes but, following their close coordination chemistry properties, have similar metabolic routes. Both make use of albumin for transport and of metallothionein at the absorption and hepatic-binding stages. In contrast to iron, copper and zinc have no well-defined storage system; instead they make use of body reserves distributed in various tissues. Our knowledge of the transport and storage systems of the trace metals is still very incomplete. More research is needed on the dynamics of movement of the trace metals between the various body tissues and fluids. Further advances will also come from the study of related metal inherited diseases in other animal species.

A comprehensive platform to investigate protein–metal ion interactions by affinity capillary electrophoresis

“…The metal ions Fe 3+ and Fe 2+ are involved in various biological complexes. Both oxidation states have different chemical properties which influence their binding site selectivity [4,26]. The high oxidation state (Fe 3+ ) is favorable to bind at sites rich in amino acid residues containing hard functional groups such as glutamate, aspartate, tyrosine and possibly histidine [27].…”

Ischemia-modified albumin: Crosstalk between fatty acid and cobalt binding

“…One of its key roles in the body is to transport a variety of small molecules, including cholesterol [28] , fatty acids [29] , and pharmaceutical drugs [30] . Importantly, albumin also serves as an important carrier of inorganic ions, including those required for regular physiological function (Ca 2+ , Cu 2+ , Zn 2+ ) [31] , toxic metal ions (Cd 2+ and Ni 2+ ) [32] , [33] , as well as metal-based therapeutics (Au + and Pt 2+ ) [34] , [35] . Before considering cobalt binding in depth, we will briefly summarise the interactions of albumin with other d-block metal ions, with the exception of Cr 3+ , Fe 3+ , and Mn 2+ , which are preferentially transported by transferrin, another important metal ion transporter in blood plasma.…”

The effect of treatment on zinc, copper and calcium status in children with phenylketonuria

“…The National Research Council (1973) recommendations are 46-77 gmot of zinc (3-5 rag), and 0.6-1.2 gmol (40-59 lag) kg-1 day-1 of copper, but these • :. (Laurie, 1983). This antagonistic action of zinc on copper absorption has, in fact, been used to inhibit copper accumulation in Wilson's disease (Van Caillie et aI., 1982).…”