Removing Blood Stains
Proteases are enzymes that are
used in a washing powder to remove blood stains. Why people used proteases
to remove blood stains instead of lipases or amylases? How do these
enzymes removed those stains( the process ) ?
I am not a specialist on detergents and soaps but here
is my understanding of this:
The compound of a blood stain that causes the coloring
is iron, bound in a protein called hemoglobin. It is
this protein that gives blood its red color, and the
iron ions captured in hemoglobin transport oxygen in
When blood dries up on cloth material, the protein
becomes denatured (is no longer in the biologically
active form) and binds to the material fibres. The
iron (no longer bright red but ironish brown) is
captured in this protein. Heating (hot washing)
fixates the protein even stronger to the tissue. It
can not be removed with normal soap which removes
grease and fat, but poorly removes protein.
Proteases degrade the protein into small bits that
come loose, and then the iron ions (the color of the
stain) are released.
Lipases degrade fat and amylases degrade
polysachharides, both would be useless to remove
Hemoglobin which is the bulk of the "blood stain" is a protein...proteases
dissolve protein...lipases dissolve lipids (fats and oils) and amylases
Peter Faletra Ph.D.
Office of Science
Department of Energy
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Update: June 2012