A Small Pathway to Invention and Discovery

For a number of years teachers and students tested for amylase in various biological sources. This has always been done using petri plates filled with starch-agar. Spit, squashed germinating seeds, etc., were applied to the surface, allowed to incubate for maybe 20 minutes to give the amylases time to diffuse into the agar and degrade the starch, and then iodine was flooded onto the surface resulting in white splotches on a dark background.

While this is simple, it still takes time and expensive agar to set it up. So something was tried. Some white paper towels had a little spray starch applied to them, stuff was squashed on them, the allow to sit atop another moist paper towel for 20 minutes, and finally sprayed with a mist of iodine solution. Voila! Dark paper towel with white splotches on it. Versus making starch-agar plates, how long does it take to apply spray starch onto paper? Mucho time and energy saved.

But then two more brilliant ideas came!

What if the starched paper towels were used as chromatography paper: apply squished whatever at the origin, and then, using saline as the "solvent", do chromatography. Development again by iodine spray. Voila! White comets should appear as the enzyme ascended the paper and grazed away the starch. (In other realms such as immuno-work, this is called rocket chromatography.) In doing this, Bounty double ply worked better than most paper towels.

Then the second brilliant idea: Because the comet or rocket could be grazed by an unknown number of different types of amylase, a way needed to be found to visualize whether there was one or more types of amylase in a person's spit, for example. Squish germinating corn and pea seeds onto the origin line of a towel, and then dab a bit of spit somewhere else on that line also. After awhile the water line should ascend about as far as it will go. Now spray the towel with starch, lay it flat on a moist paper towel for about 20 min, and then iodine spray it. This is what might be gotten:

Such a chromatogram would indicate that all three of us eukaryotes seem to possess two types of amylase - with Rf's of 0 and about 80. And I had another one at an Rf about 30.