**28. Ferritin**

Soybean seed ferritin contains a great deal of bioavailable iron and is important for human iron supplementation and prevention of anemia caused by iron deficiency. Dong et al [31] employed a rapid and simple *Escherichia coli* expression system for producing the soybean seed ferritin complex. The two subunits, H-2 and H-1, were encoded in a single plasmid, and optimal expression was accomplished by coexpressing in addition a team of molecular chaperones, trigger factor and GroEL-GroES. The His-tagged ferritin complex was purified by Ni2+ affinity chromatography. An intact ferritin complex was obtained following His-tag‐ ged enterokinase digestion [31].
