separation of biotin labelled IgG from unlabelled IgG

Carlos Duarte Carlos.Duarte at CIGB.EDU.CU
Tue Feb 2 20:01:38 EST 1999

For most applications of biotynilated IgG you dont need to separated unlabel antibodies since the reaction is quite efficient 
and you use an excess of biotin in the coupling reaction. Anyway biotinylated Abs will certainly binds to an 
affinity column with avidin or streptavidine but you will find very difficult to elute the molecule due to the very high Ka between 
biotine and avidine (10-15M). Hope it helps

Carlos A. Duarte, pHD
Head, AIDS  Department, Vaccine Division
Center for Genetic Engineering and Biotechnology
Ave 31 entre 158 y 190, Cubanacán, Playa
Apdo 6162, La Habana 10600
Fax 53-7-214764, 218070. 336008
Phone 53-7-218164, 218466, 218008
email carlos.duarte at

-----Original Message-----
From:	Dan Pashniak [SMTP:dpashnia at]
Sent:	Tuesday, February 02, 1999 12:32 PM
To:	methods at
Subject:	separation of biotin labelled IgG from unlabelled IgG

Hi there . . . 

I am looking for a method of separating hapten-labeled IgG, specifically, biotin labeled, 
from unlabeled IgG. I am considering using an affinity column bound with anti-biotin. 

It's simple to remove the unbound biotin from the reaction matrix . . . just use a good old 
PD-10 (G25) column (Pharmacia). But, what about the unlabeled IgG. Size exclusion certainly won't work; biotin is only ~250 Da. 

Would and affinity column work? 

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