corn vs arrowroot starch: pure amylose?

Marty Sachs msachs at
Sat Mar 23 15:57:22 EST 1996

I'm not sure about arrowroot, but there are a couple of mutants of maize
that may be able to help you out. Amylose extender (ae1) gives corn-starch
that is almost pure amylose, and waxy (wx1) gives corn-starch that is
almost pure  amylopectin.

In article <4j1b9r$pmc at>, brucerat at (BruceRat)

:I have been doing photometric studies of amylase degradation of amylose,
:and gotten just OK results using cornstarch (Kingsford's).   By "OK"
:results I refer to fact that my data curve does only an OK job of holding
:to the theoretical Michaelis Menten curve.  (The data seems to keep
:drifting up.)
:When I switched to using arrowroot starch, the  match between data and
:theory is excellent!     Since cornstarch is actually a mixture of amylose
:and amylopectin, the amylase has two different substrates.  Hence, I
:assume my curve is actually the sum of two curves, amylose degrading two
:my question:  Why should arrowroot starch give results that are so much
:better?  Is arrowroot starch pure amylase?
:Bruce Ratcliffe, a puzzled high school science teacher in Fresno
:(BruceRat at AOL.COM)

Marty Sachs              
USDA/ARS & Crop Sciences/UIUC    msachs at [internet]
S108 Turner Hall                  
1102 S. Goodwin Ave.             (217) 244-0864 [phone]
Urbana, IL  61801-4798           (217) 333-6064 [FAX]

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