use of BSA in... (why air kills)

Fri Sep 23 10:56:12 EST 1994

Chong-Yee Khoo wrote [in a thread about BSA stabilizing dilute proteins]:

> forgive me, but how exactly does protein get lost at liquid/air boundaries?
> i can see that proteins might stick to tubes and tips, but air?

At an air/water interface, the hydrophobic residues that stabilize globular
proteins can instead avoid water by projecting into the air.  This is why
protein solutions foam, and why an enzyme solution that has been aggitated
to the point of foaming is dead.  Whenever you hear people debate whether
it is acceptable to mix, vortex, or otherwise abuse an enzyme solution, the
rule of thumb is -- mix all you want so long as you don't make bubbles and 
keep it cold.  The air/water interface in a tube is usually not considered a
significant problem unless you expand it by making bubbles.

Steve Hardies, Dept. of Biochem., Univ. of Texas HSC at San Antonio
Hardies at

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