Hi Steve,

Liver and kidney are most likely to contain endogenous biotin.  Avidin is
from hens eggs and is not a problem.  You can block endogenous biotin with
unlabeled avidin.  See Woods GS, Warnke R. (1981) Suppression of endogenous
avidin-binding activity in tissues and its relevance to biotin-avidin
detection systems. J Histochem Cytochem 29:1196.

I also vaguely remember an article suggesting that mast cells bind to the AB
complex as well but can't trace it.

Phil Hall
St Michael's Hospital
Bristol
UK

	----------
	From:  Steve Machin UK [SMTP:stevemachinuk@yahoo.co.uk]
	Sent:  07 September 2001 12:29
	To:  Histonet Histonet Histonet
	Subject:  Endogenous Biotin and Avidin

	Could someone please give me a list of tissues which are likely to
	give background in ABC Kits because they contain endogenous Biotin
or
	Avidin.

	Best Wishes
	Steve Machin UK

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