X-Message-Number: 9753
Date: Thu, 21 May 1998 13:21:48 -0700 (PDT)
From: Doug Skrecky <>
Subject: freezing and drying denaturation of proteins Part I

Authors
  Carpenter JF.  Prestrelski SJ.  Arakawa T.
Institution
  CryoLife, Inc., Marietta, Georgia 30067.
Title
  Separation of freezing- and drying-induced denaturation of
  lyophilized proteins using stress-specific stabilization. I. Enzyme activity
  and calorimetric studies.
Source
  Archives of Biochemistry & Biophysics.  303(2):456-64, 1993 Jun.
Abstract
  Stabilization of labile proteins during lyophilization requires protection of
  the protein against both freezing and dehydration stresses. Solutions of
  1-10% (wt/vol) polyethylene glycol (PEG) fully protected both lactate
  dehydrogenase and phosphofructokinase during freezing and thawing, but did
  not stabilize the proteins during
  freeze-drying. Thus, with this
  lyophilization system a second compound could be tested for its capacity to
  stabilize dried proteins, independent of its ability to provide
  cryopreservation. In the presence of low concentrations of glucose or
  trehalose (which alone provided minimal protection) and 1% PEG (wt/vol),
  almost full enzyme activity was recovered after
  freeze-drying and rehydration. Differential
  scanning calorimetry indicated that the PEG was crystalline and the sugars
  were amorphous in the dried samples. Experiments with lactose and
  mannitol demonstrated that if these compounds also
  crystallized during freeze-drying, protein
  stabilization was reduced or abolished. PEG stabilizes the proteins during
  freezing, due to preferential exclusion of PEG from the protein's surface.
  The sugars protect the proteins during dehydration by hydrogen bonding to the
  dried protein, thus serving as water substitutes. This report provides the
  first example of stabilization of proteins during lyophilization through
  separate, specific treatments of the fundamentally different stresses of
  freezing and dehydration.

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9753