Addition of substances such as dimethylsulfoxide, glycerol, and gelatin to aqueous solutions of lactate dehydrogenase maintains enzymes in stable and fully active form when stored at 2 - 6 C

Friedman, O. M.

English

NASA Technical Reports Server

1972	 B72-10062 
NASA TECH BRIEF 
Ames Research Center 	
-4r 
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be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Stabffization of Lactate Dehydrogenase 
.
The problem: 
Many enzymes are unstable and exhibit a tendency 
to denature upon storage, even at low temperatures. 
Thus, there is a need to develop methods for pre-
serving enzymes in a stable and fully active form. 
The solution: 
Addition of substances such as dimethylsulfoxide, 
glycerol, and gelatin to aqueous solutions of the 
lactate dehydrogenase; the enzyme maintains full 
activity when stored 19 months at 2 to 6°C, whereas 
it has only 50% of its activity at the end of one month 
in the absence of stabilizers. 
How it's done: 
The criterion of stability of beef heart lactate de-
hydrogenase solutions is based on observation that 
thermal inactivation at 37°C appears to be a function 
of incubation time at selected conditions of enzyme 
concentration, pH, and buffer ionic strength. Nor-
mally, approximately 80 minutes is required for 50% 
reduction of lactate dehydrogeriase activity. The ex-
tent to which the enzyme is protected from 50% 
thermal inactivation is thus a measure of the efficacy 
of the additive under study. The stabilizing and 
labiizing effects of a series of diverse additives have 
been evaluated by this test. 
It has been found that dilute aqueous solutions 
of the dehydrogenase are stabilized by additions of 
various organic additives. Dimethylsulfoxide is es-
pecially effective in concentrations of 20 to 40 per-
cent by weight. For example, in the presence of 
40-percent dimethylsulfoxide, beef heart lactate de-
hydrogenase retained about 65 percent of its original
activity after storage for 20 months at 4 ± 2°C. 
Lower concentrations are less effective; in the pres-
ence of 20-percent dimethylsulfoxide, all activity is 
lost in 18 months. 
The stabilizing property of dimethylsulfoxide sug-
gested a study of other additives, and it was found 
that the inclusion of gelatin enhanced stability still 
further. For example, beef heart lactate dehydro-
genase retains virtually all of its activity when stored 
19 months in aqueous 40-percent dimethylsulfoxide 
solutions containing 0.5 percent gelatin; under sim-
ilar storage conditions, aqueous solutions retain only 
10 percent of the initial activity. 
Glycerol, ethyl, and methyl alcohol, isobutanol, etc. 
are also useful stabilizers; bovine serum albumin may 
be used in place of gelatin. However, each stabilizing 
system has to be evaluated for the particular enzyme 
that is to be preserved. 
Reference: 
George, H.; McMahan, J.; Bowler, K.; and Elliott, 
M.: Stabilization of lactate and malate dehydrog-
enase by organic solvents. Biochimica et Biophysica 
Acta, vol. 191, page 466, 1969. 
Notes: 
1. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: NASA CR-78460 (N70-31057), 
Studies on Stabilization of Enzymes. 
(continued overleaf) 
This documefct was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
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2. No additional documentation is available. Specific 
questions, however, may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: B72-10062
Patent status: 
No patent action is contemplated by NASA. 
Source: 0. M. Friedman of

Collaborative Research, Inc.

under contract to

Ames Research Center 
(ARC-10415)
. 
Category 05


Stabilization of lactate dehydrogenase

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