Protein Low Binding Tubes “PROKEEP”

Manufactured by Watson’s proprietary precision tooling and materials.
A high quality tube with protein low binding properties.

What are PROKEEP Protein Low Binding Tubes ?

PROKEEP is designed for protein or peptide analysis (SDS-PAGE, HPLC, MS). It mitigates the risk of sample loss and improves the signals obtained.

Our special blending plastic materials avoid problem caused by elution from the tube.

We have successfully developed a proprietary blend for protein and peptide low-adsorption resin, along with precision finishing of molds, which reduces protein adsorption without the need for surface treatment.
This innovation allows us to avoid issues caused by leachables from tube materials in other companies’ low-adsorption types (hydrophilic-treated products) and achieve excellent results in MALDI MS analysis and Protein Chip analysis.

PROKEEP 1.5 mL (PK-15C-500N)

Material:virgin polypropylene
Maximum centrifugal force: 20,000 x G (water 1.0 mL / 15 minutes)
RNase/DNase/Human-DNA free
PROKEEP 2.0 mL (PK-20C-500)

PROKEEP 2.0 mL (PK-20C-500)

Material:virgin polypropylene
Maximum centrifugal force: 7,000 x G (water 1.5 mL / 15 minutes)
RNase/DNase/Human-DNA free

Cat. No.ItemUnit
PK-15C-500NPROKEEP protein low binding tube 1.5 mL, Flat Bottom, Natural, Bulk pack500 tubes / bag
PK-20C-500PROKEEP protein low binding tube 2.0 mL, Round Bottom, Natural, Bulk pack500 tubes / bag

PROKEEP’s Protein Low Binding performance

Protein and peptide loss when using plastic containers is caused by 2 factors.
(1) Solution residue that has not been collected by pipetting and centrifuge operation.
(2) Protein and peptide bonded to the containers
Many conventional container manufacturers have focused their development on either one of the above, but at Watson we have successfully addressed both factors.

Watson’s PROKEEP containers are incomparable at in terms of achieving a low residue signal. PROKEEP’s residue Signal is approximately 1 / 20 mill, which is 1 / 850 residue amount of other company’s hydrophilic products in factor (1). No occurrence of peptide signal loss during 2 weeks-storage in factor (2)

(1) Residue Protein Amount: Fig 1

Test Method:

FITC-BSA solution (1 µg / mL) was put in a microtube and left for 1 hour at room temperature.
The fluorescence of the surface of the tube was measured and digitized after removal of the solution, and then the residual protein mass was analyzed. This method evaluates the residual amount on the surface of the tube.


The residue amount on PROKEEP low protein binding tube is extremely small, which is 1 / 20 mill of the protein added.
Tubes with hydrophilic surface treatment exhibited higher residue amount due to characteristic of the treatment.

(2) Adsorption of protein and peptide to the tube: Fig 2

Test Method:

A solution(0.1%TFA, 10 µL) equivalent to 500 fmol / µL peptide mix contained in Bruker Daltonics’s Peptide calibration standard(#206195) was put in a tube and kept at 4℃ for 2 weeks.
Then, the peptide in the tube was collected and analized by mass spectrometer(Bruker Daltonics’s Ultraflex tof/ tof).


In the case of PROKEEPs protein low binding tube, all the peaks were detected after the 2 weeks.
Our competitor’s low binding tubes showed a part of the peaks were undetectable and peptide loss by binding was observed (Fig 2B).

(3) Crystallization on MALDI Target Plate: Fig 3

Test Method:
In the crystalyzation process on a target plate, which is the indispensable process of MALDI type mass spectrometer analysis, a sample collected from another company’s hydrophilic treated tube exhibited a disturbance in crystalization and it was difficult to conduct an accurate measurement, and elution of resin content was suspected(Fig. 3).
protein low binding tube showed equivalent performance to the tube recommended by Bruker Daltonics.

Product Inquiry

※We also accept inquiries for mass production development of custom shapes, such as OEM and ODM, for plastic products.