I use your SNAP-25 protein routinely in my experiments using a frozen stock that I keep at -80C. It works fine. However, for my experiments I cleave the SNAP-25 (lop off the last 10 aa or so) and use this protein for my ELISA. I cleave the SNAP-25 by incubating it for 2 hours with the 50KD Enzymatic light chain from Botulinium toxin A. The fresh cleaved SNAP-25 works fine in my ELISA. When I take 0.5 mg/ml of the cleaved SNAP-25 (also containing 0.25 mg/ml toxin A) and freeze it at -80C in 25 mM Tris-HCL, 1 mM DTT, 2 mM EDTA, and 10% glycerol (your formulation for SNAP-25) I lose 70% of my activity in 3 days. Do you have any tips on how to store this cleaved SNAP-25? Preparing the product fresh every time is not practical!

Name: Recombinant Human SNAP25 Protein
Brand: Novus Biologicals
SKU: NBC1-18344

I imagine that the loss of activity comes from storing the protein in the presence of Botulinum toxin A and not from freeze thawing. Have you tested that activity remains after a round of freezing and thawing in the absence of the toxin? In this situation, I think you need to remove the Botulinum toxin since even at -80C, the toxin could be continuing to cleave and destroy the protein. The toxin you said is 50kDa, and the protein is 25kDa. Could you remove the toxin by size exclusion chromatography? Additionally, I found this paper, Procedures for the Inactivation and Safe Containment of Toxins (http://www.ouhsc.edu/ehso/toxinproc.pdf) that suggests that you can inactivate the toxin by heating or by adding sodium hypochorite and/or sodium hydroxide. I know this protein can be used for Western blot, so it should be able to survive boiling but 200 degrees Celsius may be too much but could be worth trying on an aliquot? Size exclusion chromatography, bleaching and heating are our three suggestions at the moment. If none of these work, then you may have to continue to prepare it fresh.

Recombinant Human SNAP25 Protein

Novus Biologicals, part of Bio-Techne | Catalog # NBC1-18344

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Product Specifications
Scientific Data
Preparation & Storage
Background
Product Documents
Specific Notices

Key Product Details

Source

E. coli

Conjugate

Unconjugated

Applications

SDS-PAGE

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Product Specifications

Description

An un-tagged recombinant protein corresponding to the amino acids1-206 of Human SNAP25

Source: E.coli

Amino Acid Sequence: MAEDADMRNE LEEMQRRADQ LADESLESTR RMLQLVEESK DAGIRTLVML DEQGEQLERI EEGMDQINKD MKEAEKNLTD LGKFCGLCVC PCNKLKSSDA YKKAWGNNQD GVVASQPARV VDEREQMAIS GGFIRRVTND ARENEMDENL EQVSGIIGNL RHMALDMGNE IDTQNRQIDR IMEKADSNKT RIDEANQRAT KMLGSG

Purity

>90%, by SDS-PAGE

Predicted Molecular Mass

23.3 kDa.
Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.

Protein / Peptide Type

Recombinant Protein

Scientific Data Images for Recombinant Human SNAP25 Protein

SDS-PAGE: Recombinant Human SNAP25 Protein [NBC1-18344]

SDS-Page: SNAP25 Protein [NBC1-18344] - SNAP25, 23 kDa (206 aa) , confirmed by MALDI-TOF with a purity of 90% by SDS - PAGE

Formulation, Preparation and Storage

NBC1-18344

Formulation	25mM Tris-HCl buffer (pH 7.5), 1 mM DTT, 10% glycerol
Preservative	No Preservative
Concentration	1 mg/ml
Shipping	The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage	Store at 4C short term. Aliquot and store at -20C long term. Avoid freeze-thaw cycles.

Background: SNAP25

The synaptosomal-associated protein (SNAP-25) is an essential component of the core complex that mediates presynaptic vesicle trafficking. Thus, SNAP-25 is directly involved in the release of neurotransmitters and this protein exists as two alternative isoforms, SNAP25A and SNAP25B which differ by 9 amino acids in central portion of these proteins. Recombinant SNAP25B protein was expressed in E.coli and purified by using conventional chromatography techniques.

Long Name

Synaptosomal-associated Protein, 25 kDa

Alternate Names

RIC4, SEC9, SUP

Gene Symbol

SNAP25

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Product Documents for Recombinant Human SNAP25 Protein

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COA

Product Specific Notices for Recombinant Human SNAP25 Protein

This product is for research use only and is not approved for use in humans or in clinical diagnosis. This product is guaranteed for 1 year from date of receipt.

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