TCA Precipitation

Peter pxpst2 at
Wed Oct 15 08:48:04 EST 1997

In article <344412D3.429EB6F9 at>,
yip at wrote:

.> Does anyone know the lower limit for molecular size peptides which may
.> be precipitated by method of TCA precipitation?
.> That is, what's the smallest peptides which may be precipitated by TCA?
About 20 KD.  But the amt. of glycosylation matters and the aa
composition.  TCA precipitation is different for each protein/peptide.  My
protein HGF does not precipitate well at low concentrations (<1ug/ml)
while BSA precipitates well at half that.  Personally, I find TCA
precipitation to be unreliable and not good for precipitating proteins at
low concentrations and/or small molecular weight.  The best procedure that
I have found for the recovery of ng  quantities of protein(of any size) is
Phenol/ether extraction.  I have successfully recovered 15 ng from 1 ml. 
TCA cannot do this.


"Don't you eat that yellow snow
    WAtch out where the Huskies go"


Let us not forget those marketing boys from SPAM CENTRAL

bestrealtor at
info at
clickthru at
invite at
zippydj at
Offer at
empower at
dynamarket at
root at
cashrewards at

More information about the Methods mailing list