Wanted: "Good" buffers for pH <5.5

D.Lippert lippy at UVic.CA
Thu Nov 21 12:09:35 EST 1996


goldie at duke.usask.ca (Hugh Goldie) wrote:

>I need a buffer for enzyme assays in the range of pH of 4 to 5.  The buffers
>recommended by Dr. Good in Methods in Enzymology and other articles list
>succinate, but this is an inhibitor of the enzyme.  Acetate, citrate and
>phthalate also either inhibit the enzyme or bind cofactor metals (Mg and Mn)
>too tightly.  It is probably best to avoid compounds with carboxyl groups.
>Phosphate, with pK's of 1.9 and 6.7, does not quite fill the bill --it also
>binds metals significantly (Ka's of 1.9 to 9.6) for different complexes.

>Please send any suggestions to me by e-mail.

>Hughes Goldie, University of Saskatchewan, Saskatoon, Canada
>E-mail:  goldie at duke.usask.ca

pyridine has a pka of 5.2, so it should work well down to 4.2 or so.
I can't say I've ever used it, but I know others do.  It's somewhat
bad for you, so use it in the hood (it stinks, so you'll want to
anyway).  

Dustin




More information about the Methods mailing list