Re: peptides

From:Tamara Howard

Hal - You are saying that you used this peptide-specific antibody on sheep
and got staining, even though the peptide sequence to which the antibody
was made is not present in the sheep protein? Have you tried blocking
with the peptide to be certain that the staining you see in sheep is real?
Or, do you have a null sheep that you could test? Have you done a blot
with the antibody and only seen one real band?

The only way that the antibody could be staining "for real" would be if
some folding of the protein in sheep may occur that would be create the
same sequence as in the missing peptide or if there is enough of the same
sequence for the antibody to bind - but I think the folding idea is sort
of like waiting for the hypothetical monkeys with typewriters to create
the complete works of Shakespeare! But, it might happen. Or if the
published sequence is wrong......I'm guessing that you may be seeing some
other protein. Have you searched the sheep databases to see if this
peptide shows up in another protein?


> ----------------------------------------------------------------------
> Date: 22 Sep 2002 14:15:50 -0500
> From: "Hawkins, Hal K." 
> Subject: peptides
> Recently it has been suggested that in selecting an antibody to detect
> an antigen in another species, a search for a matching peptide sequence
> may be necessary.  Specifically, we used a rabbit polyclonal antibody
> raised to a 14-peptide chain from mouse iNOS, and obtained selective
> staining with a reasonable pattern in the sheep.  It was suggested that
> since we could not find this a matching sequence in the sheep protein,
> the antibody should not be used.  I would greatly appreciate
> the comments of the group on the usefulness of this kind of criterion.
> Hal Hawkins, UTMB Galveston

 Tamara Howard
 Department of Cell Biology and Physiology
 University of New Mexico - Health Sciences Center
 Albuquerque, NM 87131

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