Starch-iodine complex

Nancy Harrison vulpia at
Sun Apr 5 20:45:14 EST 1998

Thanks Jon - this is great information and I can look it up now (never
thought of Salisbury and Ross!). I think the Kakefuda et al paper may
be a bit beyond me but that's a great ref to have. Cheers! -NH

>Nancy and other inquiring minds;
>My understanding is that amylose (the nearly unbranched form of starch)
>forms a helix with six glucose units per turn (see Salisbury and Ross,
>Plant Physiology 4th ed. page 247).  Iodine gets into the middle of the
>"tube" and in that environment appears blue or purple.  Amylopectin (the
>branched form of starch) can be purple or red with iodine stain.
>You can see an beautiful example of this in a paper by Kakefuda and Duke
>(Plant Physiology 75: 278-280, 1984) in which they ran various starch
>hydrolases on a nondenaturing polyacrylamide gel, then electrophoretically
>transferred the enzymes through a second polyacrylamide gel containing
>starch (like a western transfer).  The enzymes partially chew "holes" in
>the starch as they go and after staining the second gel with iodine the
>holes appear blue, brown, grey or red.  It is a very nice technique but one
>must wear a mask or not talk when setting it up because salivary amylases
>can speckle the second gel with white spots!
>  Jonathan Monroe                voice:  540-568-6649 (office)
>  Department of Biology                  540-568-6045 (lab)
>  James Madison University       fax:    540-568-3333
>  Harrisonburg, VA 22807-0001    e-mail: monroejd at

---Nancy Harrison, SRJC Life Sciences, Santa Rosa CA 95401 (with link to CNPS in Sonoma 

More information about the Plant-ed mailing list