Transendothelial Transport and Its Role in Therapeutics

Table 1

Cellular functions of various kinds of metal and nonmetal ions inside cell and its transport mechanisms.

Element	Ionic form	Transport mechanism	Functions	References
Molybdenum		Ion transporters	Cofactor or activator of certain enzymes (e.g., nitrogen fixation, nucleic acid metabolism, and aldehyde oxidation)
Cobalt	Co^2+	Ion transporters, DMT1	Constituent of vitamins B12
Copper	Cu^+, Cu^2+	ATP 7A catalyzes, Cu-transporting ATPase	Constituent of plastocyanin and cofactor of respiratory enzymes.	[28–32]
Iodine (heaviest trace element)	I	Diffusion and ion transporters	Constituent of thyroxin, triiodothyronine, and other thyroid hormones.
Boron	,	Ion transporters	Activates arabinose isomerase.
Zinc	Zn^2+	Enzyme and protein carriers	Cofactor of certain enzymes (e.g., carbonic anhydrase, carboxypeptidase)
Manganese	Mn^2+, (Mn^2+).4	DMT1	Cofactor of certain enzymes (e.g., several kinases, isocitric decarboxylase).
Iron	Fe^2+, Fe^3+	DMT1	Constituent of haemoglobin, myoglobin, and cytochromes.
Magnesium	Mg^2+	Ion transporters	Constituent of chlorophyll activates ATPase enzyme
Sulphur		Ion transporters	Constituent of coenzyme A, biotin, thiamine, and proteins.
Phosphorus	, H2PO4	Ion transporters	Constituent of lipids, proteins, nucleic acids, sugar phosphates, and nucleoside phosphates.
Calcium	Ca^2+	Ion transporters	Constituent of plant cell walls; matrix component of bone tissue; cofactor of coagulation enzymes.
Potassium	K^+	Diffusion and ion channels	Cofactor for pyruvate kinase and K^+-stimulated ATPase.
Sodium	Na^+	Diffusion and ion channels	Perform nerve functions, acid base balance, and homeostasis
Cadmium	Cd^2+	DMT1
Zinc^2+	Zn, ZIP6 (LIV-1)	Zinc transporters	Metabolic cellular functions	[33]
Aluminium	Al	Transferrin-receptor mediated endocytosis
Metal ions	Fe, Cu, and Ag	Multiple transport proteins, Na^+/K^+ pump, K^+ channel, Na^+ lysine symporter channel, and sodium-lysine transporter	Work as electrolyte in plasma	[34]
Metal ions	Fe, Cu, and Ag	Membrane transporter proteins such as ABC transport proteins	Enzymatic cellular functions	[35]
Free metal ion and complexes	Fe, Cu, Ag oxides, and sulphates	Transferrin carries metal species, such as the free metal ion and complexes of the metal with an amino acid or protein.	Transmigration of proteins	[36, 37]
Divalent metals	Fe, Cu, Ag, and zinc	(DMT1, DCT1, and Nramp2) transports, ferroprotein,		[36, 38, 39]
Divalent metals	Fe3+ and cobalt (Co2+), Ca++, Fe++, Mn++, Cd++, Cu++, Ni++, Pb++, Zn ++	Divalent metal transporter 1, divalent cation transporter 1 (DCT1)	Iron-overload disorders	[40, 41]
Trivalent metals	Al and Mn	Diferric transferrin		[42]
Methyl mercury		Transport by the L-cysteine system		[43]