[Histonet] Diastase

[John Kiernan]

Why buy?  Just think of squeezing a chunk of lemon over your helping of haddock and drool into a small beaker. Remove bubbles by wiping the surface of the collected liquid with the edge of a piece of filter paper. Incubate for 30 minutes at 37C, just the same as for 0.1% malt diastase.

Saliva also contains RNase, but this doesn't matter because RNA is not stained by PAS or by other methods for staining glycogen. For a cheap source of RNase you can heat the collected saliva (80C for 10 minutes) to inactivate diastase and any other enzymes. Cool and centrifuge. Use the supernatant at 37C for 1 hour.

Some references.

Bradbury S (1956) Human saliva as a convenient source of ribonuclease. Quart. J. Microsc. Sci. 97: 323-327.  (Free PDF available at https://jcs.biologists.org/content/s3-97/39/323.short).

Brown, GG (1978) An Introduction to Histotechnology. New York: Appleton-Century-Crofts. pp. 302 (diastase) & 292 (ribonuclease).

Drury RAB, Wallington EA (1967) Carleton's Histological Technique. 4th ed. Oxford University Press, Oxford. pp.163-164 (ribonuclease) & 208 (diastase).

John Kiernan
Dept of Anatomy & Cell Biology
University of Western Ontario, London, Canada
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________________________________
From: Paula via Histonet <histonet at lists.utsouthwestern.edu>
Sent: 26 November 2019 12:16
To: histonet at lists.utsouthwestern.edu <histonet at lists.utsouthwestern.edu>
Subject: [Histonet] Diastase

Hello,



We've been using STATLabs Diastase for our PAS with diastase digestion but
they have a backorder until January. Can anyone recommend an alternative
from other vendors?



Thank you in advance,

Paula

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