Enzymes Storage Best Practices - Medical Refrigerators and Freezers Help to Prevent Premature Degradation

Enzymes Storage Best Practices - Medical Refrigerators and Freezers Help to Prevent Premature Degradation

Apr 11th 2022


Enzymes are proteins that act as a catalyst in other chemical reactions. Often referred to in the research community as biological catalysts, enzymes are naturally occurring in most biological lifeforms. They spur necessary chemical changes needed for life-sustaining activity in both plant and animal cells.

Enzymes play a significant role in many organic biological processes, but they are also used as a research tool. Enzymes activity in seen in the context of seed germination, the ripening of fruit, digestive processes, and the reproduction and growth of animals and plants. Enzymes are even used in toothpaste!

The decomposition and decay process of organic materials is fueled by the presence of enzymes. This is one of the reasons why proper cold storage is a paramount because enzymes can quickly start this decaying process in perishable products. Used in many research applications, enzymes are used to encourage certain kinds of biological activities and processes through the course of experimentation.

Enzymes used in this capacity are typically housed in dedicated enzyme refrigerators to prevent premature degradation. The types of enzymes studied by researchers must be stored in a lab freezer or an enzyme freezer at temperatures in the region of -10 to -25˚C (+14 to -13˚F). When stored at higher temperatures enzymes gradually denature and lose catalytic activity.

Enzyme Types

There are six kinds of enzymes, each producing a specific chemical reaction. Enzymes are classified by the type of reaction they catalyze. For example, die enzyme lactase acts a catalyst for lactose and converts it into lactic acid, resulting in soured milk. Most enzyme types listed below require some type of optimized cold storage, such as those found in laboratory-grade refrigerators and freezers.


The enzyme oxidoreductase catalyzes the oxidation reaction where the electrons tend to travel from one form of a molecule to the other. Examples of oxidoreductase enzymes include, peroxidases, hydroxylases, oxygenases, and alcohol oxidoreductases.

Highlighted for their potential is the production of renewable building blocks from plant biomass and their use for the manufacture of sustainable chemicals and materials in lignocellulose biorefineries, they tend to have complex storage requirements.


The transferases enzymes help in the transportation of the functional group among acceptors and donor molecules. Examples of transferases include riboflavin synthase and chlorophyll synthase.

The storage temperature of -70 degrees C in a laboratory-grade ultra-low freezer unit was found in clinical studies to guarantees the best stability.


Hydrolases are hydrolytic enzymes that catalyze the hydrolysis reaction of a substrate by adding water to cleave the bond and hydrolyze it. Examples of hydrolase enzymes include Esterases including lipases, phosphatases, glycosidases, peptidases, and nucleosidases.

Hydrolases are best stored at –20 °C.


Lyase is an enzyme that breaks apart various chemical bonds by means of an "elimination" reaction. Lyases are different from other enzymes for only one substrate is required for the reaction in one direction, but two substrates are essential for the reverse reaction. Examples of Lyase include decarboxylase, dehydratase, and aldolase.

The cold storage recommendations vary on Lysase enzyme samples depending upon short- and long-term storage needs. For ultimate long-term preservation, ultra-low freezer housing at -80°C is optimal. Most experts advise pairing the lysase samples with certain reagents to assist with stabilization.


A Ligases is an enzyme that catalyzes the bonding of two large molecules. Examples of ligases are Threonyl-tRNA synthetase, Acetyl-CoA carboxylase, and Succinyl-CoA synthetase.

Ligation reactions are optimal at 12 to 16 °C. Performing ligation reactions at this temperature helps to maintain stability. High-performance refrigerators options for enzyme housing of this type are available at K2 Scientific.


An Isomerases is a type of enzymes that changes a molecule from one isomer to another. Examples of isomerases include triose phosphate isomerase, bisphosphoglycerate mutase, and photoisomerase. Isomerases can help prepare a molecule for subsequent reactions such as oxidation-reduction reactions.

Dilution of this type of enzyme in a buffered solution and stored at –20 °C. At this temperature, the enzyme is shown in clinical studies to retains activity for at least two years.

Enzyme Research and Diagnostic Applications

In the research community, it was believed that enzymes were primarily just proteins. However, in the late 1980s, it was discovered that ribonucleic acid (RNA) molecules were also capable of inducing catalytic reactions. RNAs (ribozymes) are a vital component in gene expression.

Following more research gains, the scientific community developed technology to generate antibodies capable of harnessing those same catalytic properties. Termed as ‘abzymes’, they possess significant potential serving as industrial catalysts and towards the development of advanced therapeutics.

Research is the backbone of novel drug development strategies. As technology improves, so does the ability to harness a greater comprehensive view of enzyme activity. Known as important biomarkers in many advanced diseases such as myocardial infarction, pancreatitis, cancer, and neurogenerative disorders, enzymes provide researchers with clues regarding their mechanism of action.

K2 actively supporting our scientific partners in this preservation process by providing high-performance laboratory-grade refrigeration and freezers for the common goal of creating better patient outcomes.

Hemolytic Anemia

The most commonly defective enzyme, glucose-6-phosphate dehydrogenase (G6PD), is the subject of many high-value clinical studies whereby they are studying the reactions at both a biochemical and molecular level. Many other enzymatic defects have been reported, but the rarity of the disorders has hindered investigation. Enzymatic defects of the RBC known to be associated with hemolytic anemia. A few of the enzyme deficiencies cause abnormalities in other tissues.

The result of these defects is hemolytic anemia of varying severity, sometimes called hereditary non- spherocytic anemia. The RBCs may be morphologically normal and usually produce normal results on osmotic fragility testing, but they have a shorter life span. The milder cases cause little difficulty in the neonatal period. Some defects are associated with chronic and/or severe hemolysis, necessitating intermittent or chronic blood transfusions.

Coronavirus NAT Testing

Enzyme products are integral component in NAT testing and obtaining an early diagnosis of coronavirus. The World Health Organization (WHO) officially announced the COVID-19 outbreak to be a pandemic on March 11, 2020. The pandemic is changing the platform for molecular antibody products and therapeutics, and enzymes contribute towards these applications.

Currently, two methods are used to diagnose the presence of coronavirus, the nucleic acid test (NAT) and the serological test. Professional enzyme companies specialize in providing enzyme testing materials to help in this endeavor.

Understanding Enzyme Instability

Mitigating DNA (Taq) Enzyme Polymerase degradation is a bit tricky. There are many schools of thoughts circulating among the scientific community on how to keep samples safe during experimentation. Enzymes do not fare well in humid or high-temperature environments.

Studies show that elevated temperatures affect the efficiency of enzymes and allow bacterial growth causing premature degradation. At room temperature the efficiency of enzyme will decrease rendering it not very practical for long term storage, but housing enzymes in refrigerated condition provides a longer shelf life.

Using high performance refrigeration and freezer storage is the best way to achieve some type of enzyme stabilization. Due to the various enzyme types, there is not a one temperature fits all type of guidance recommendation. However, most experts agree that enzymes are so unstable that cold-storage considerations need to be a priority.

Antibody and Enzyme Medical Refrigeration Best Practices

In most circumstances, storing enzymes usually involves -20°C temperatures, and the addition of glycerol to prevent protein denaturation. Many scientists consider working with enzymes to be tedious but necessary because of their complex storage needs. It is widely accepted that medical freezers are the best way to ensure safe keeping.

Determining the best conditions for long-term storage of peroxidase-labelled immunoglobulins for use in enzyme immunoassays have been the subject of clinical investigation. The emphasis is primarily on the preservation of the immunological and enzyme activity. The best results were obtained with conjugates stored as ammonium sulphate precipitates at 4 degrees C.

Under these conditions, the complexes retained after 2 years of storage 92 and 91% of their enzymatic and immunological activity respectively and gave excellent reproducibility in ELISA (enzyme-linked immunoassay).

In contrast, storage at higher temperatures, showed a greater decrease in enzymatic than immunological activity, but the results obtained with the ammonium sulphate precipitates yielded better results than those obtained with alternative storage procedures.

About Enzyme Refrigerators and Freezers

Because enzyme materials are highly unstable, finding appropriate laboratory grade cold storage is vital to safeguard your samples. There are many options to choose from, each with their own unique benefits. To help you find the right equipment for your lab and materials, we hope you will check out the K2 guide to the different lab refrigerators and freezers.

High-performance refrigerators and freezers are designed to ward off humidity and keep temperatures variances to a minimum. They often come equipped with sophisticated features such as such as glass doors, interior insulation, and temperature alarms. For the win, many find our offerings are readily available, making sourcing the perfect unit an easy task.

For more information, please contact one of our experts team members at K2 Scientific today.

  • 1.Robinson, Peter K. “Enzymes: principles and biotechnological applications.” Essays in biochemistry vol. 59 (2015): 1-41. doi:10.1042/bse0590001
  • 2.Jung K, Kühler S, Klotzek S, Becker S, Henke W. Effect of storage temperature on the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase in rat liver and kidney homogenates. Enzyme Protein. 1993;47(3):149-55. doi: 10.1159/000468670. PMID: 8087206.

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