You want to maintain a high enzymatic activity in your Taq stock solution. If stored at room temperature your stock solution would lose activity much faster compared to deep-frozen storage. True, Taq is subject to high temperatures during PCR but here you use the enzyme and discard it subsequently when you purify the amplification product(s).

Cheers, Christian

Thank you Christian :)

I think that Taq is extremely stable and in terms of activity can be stored for long periods at room temperature. Some companies used to send Taq out at room temperature but users were unhappy with this for little good reason. The risk of high temperature storage is not that the enzyme is unstable but that opening the tube will make the enzyme ( usually in glycerol ) non sterile and bacterial growth will degrade the enzyme

Thank you Paul for sharing the valuable information.But from the point of view of two researchers discussed here.Both have different opinions..Can we find a common solution ?

I do not think that there is a common solution as scientists will always have their own feelings about things and will usually err on the side of safety but as one example i include information from genscript about theit Taq polymerase although after they say shipping at RT or even 37c is OK storage is recommended at -20. As yet I do not know of anyone shipping dried in trehalose sugars which would stabilise the enzyme much better but I knoe that Abgene shipped at ambient temperature in the UK many years ago.

Below is info from Genscript indicating that shipping at 37c for 1 week does not affect the enzyme activity.

best wishes

Paul

E00043

Green Taq DNA Polymerase

1000 U

$60

E00007-50000

Taq DNA Polymerase

50000 U (50 x 1000 U)

$2,700

E00007-1000

Taq DNA Polymerase

1000 U

$60

Taq DNA Polymerase IS a thermostable DNA Polymerase isolated FROM an E. coli strain that carries the Taq DNA polymerase gene. Taq DNA Polymerase IS the most common polymerase used FOR PCR.

Note: This product IS supplied WITH 10X reaction buffer containing 15 mM magnesium chloride. dNTP (10 mM) mixture must be ordered separatelyApplications

The applications of Taq DNA Polymerase include the following:PCR*

3'A-tailing of blunt ends

Primer extension

DNA sequencing

Formulation

GenScript Taq DNA Polymerase has been formulated using GenScript's proprietary technology. The enzyme can be shipped at room temperature or even 37°C for seven days without any loss of activity.

Unit Definition

One unit is defined as the amount of enzyme that can incorporates 10 nmol of dNTP into acid-insoluble material in 30 minutes at 74°C.

10 X Reaction Buffer (with Mg2+)

500 mM KCl, 100 mM Tris HCl (pH 9.0 at 25°C), 15 mM MgCl2, 1% Triton X-100

Buffer. This buffer is optimized for use with 200 µM dNTPs.

Note: If the reaction is performed without this buffer, then add 0.1% Triton X-100 (final concentration) to ensure high activity.

Concentration:

Taq is delivered in 5 units/µl in 20 mM Tris HCl (pH 8.0), 0.1 mM EDTA, 1 mM DTT, 0.1% Triton X-100 and 50% glycerol.

QC Tests

PCR* performance, activity, nuclease

It also depends on what time of Taq you are using, if you are using HOT-START Taq you can store them at room temperature without any obvious consequences. I think also both arguments from Paul and Christian are correct. You want to avoid contaminations and also keep your enzyme as efficient as possible.

Best regards

At room temperature the efficiency of enzyme will decrease and it will be not useful for long term. but if we store it in refrigerated condition, then we can use it for long time.

Taq Polymerase is well known for its thermostability. It maintains activity at higher temperature. Recombinant Taq pol purification makes use of this thermostability (heating at 75 -85°C for 1 - 2 hours) to denature the contaminating bacterial proteins.

I agree with paul's comment that the reason for loss of activity could be due to contamination from handling (bacterial growth, protease activity). Still some of the manufacturers ship Taq polymerase at room temperature.

Not sure about this, Antibody based Taq Pol (Hot-Start) need to be stored -20°C as the antibody is not stable at room temperature.

Taq pol is stable at high temperaturs but it does degrade during heating. It's halflife at 95C is 40min -long enough for 30-40cycles of denaturation during PCR. I don't know what its hlaflife is at 25C, but if you were to store it at RT for a year I would expect it to degrade to a considerable extent. 

I agree with Paul's views. Taq polymerase is not likely to get denatured at RT by itself but some proteases may accidentally get in to the vial (through bacterial contamination or from fingertips) which can potentially degrade the enzyme thus destroying the activity.  As a corollary, some people, in their home kitchen, store pulses at 4 degrees Celsius just to reduce the possibility of pulse beetles getting in and destroying them.