isozyme definition

Phil Harrison arsphys at CC.USU.EDU
Wed Sep 3 11:23:45 EST 1997

Robert DiSilvestro wrote:

>I am reviewing a paper where the term "isozymes" is being used
in a way I 
>do not typically use it.  I'm not sure if my limited use is
correct.  I tend 
>to use the term for enzymes with similar catalytic activity,
but fairly subtle 
>structural differences.  Would one apply the term to 3 enzymes
>have totally different structures, but the same catalytic

My tendency is the same as yours, but may I throw another term
the ring?  Namely:  --isoforms-- .   I have understood this term
to apply
to very closely related forms of the same enzyme, differing
perhaps in
a single amino acid, or just a few, resulting in a slight shift
in isoelectric
point.  So in an IEF gel you could get a group of closely
separated bands
with the same activity.  How does this fit in with isozymes?

Phil Harrison
arsphys at

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