preproproteinmedical dictionary

<biochemistry> A precursor to an inactive secretory proprotein.

A preprotein is a form that contains a signal sequence that specifies its insertion into or through membranes.

A proprotein is one that is inactive, the full function is only present when an inhibitory sequence has been removed by proteolysis. A preproprotein has both sequences still present and usually only accumulate as products of in vitro protein synthesis.

(22 Sep 2002)