Protoheme extraction from plant tissue.

A method for reproducibly estimating the protoheme content of plant tissues has been developed. The tissue sample is homogenized in 80% acetone to remove pigments and lipids; protoheme is then extracted from the tissue residue with 2% HCl in acetone and quantitatively transferred into diethyl ether. After evaporation of the ether, the residue is dissolved in alkaline pyridine, and the protoheme concentration is estimated from a dithionite-reduced-minus-ferricyanide-oxidized spectrum. When compared to some other methods, this procedure gives consistently higher yields.