Protein Laboratories Rehovot Ltd.
May 2019

Certificate of Analysis & Data Sheet

We are the ONLY company producing leptin antagonists and leptins of farm animals including several fish species.

Pegylated human, mouse, rat and ovine leptins and corresponding leptin antagonists are now available!!!

PLR provides a novel service of pegylation of either existing, or provided or custom-made proteins. All PLR's proteins are carrier free (cf) and can be sold in any requested amount !!!
Mouse leptin antagonist (mutant L39A/D40A/F41A) - Cat no. LAN-3 GENE ID 16846
Description: Recombinant mouse leptin, one polypeptide chain containing 146 amino and additional Ala at N-terminus acids and having a molecular mass of ~ 16 kDa, recombinant mouse leptin was mutated, resulting in L39A/D40A/F41A antagonist that was purified by proprietary chromatographic techniques. according to Salomon et al (2006) Protein Expression and PuriWcation 47, 128–136. 
Source: Escherichia coli. 
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Physical Appearance: White lyophilized (freeze-dried) powder. 
Formulation: The recombinant protein was lyophilized from a concentrated (0.65mg/ml) solution with 0.003mM NaHCO3. 
Solubility: It is recommended to reconstitute the lyophilized recombinant mouse leptin antagonist in sterile water or sterile 0.4% NaHCO3 adjusted to pH 8-9, not less than 100µg/ml, which can then be further diluted with other aqueous solutions.  
Stability: Lyophilized recombinant mouse leptin antagonist although stable at room temperature for several weeks, should be stored desiccated below -20C. Upon reconstitution at > 0.1 recombinant mouse leptin antagonist mg/ml and up to 2 mg/ml and filter sterilization recombinant mouse leptin antagonist can be stored at 4C or even room temperature for several weeks making it suitable for long term infusion studies using osmotic pumps. At lower concentration of recombinant mouse leptin antagonist addition of a carrier protein (0.1% HSA or BSA) is suggested. Please prevent freeze-thaw cycles. 
Purity: The purity of recombinant mouse leptin antagonist is greater than 98.0% as determined by:
(a) Gel filtration analysis.
(b) Analysis by reducing and non-reducing SDS-PAGE gel. 
Amino Acid Sequence: The sequence of the first five N-terminal amino acids of recombinant mouse leptin antagonist was determined and was found to be Ala-Val-Pro-Ile-Gln 
Dimers and Aggregates: The purified recombinant mouse leptin antagonist (16K) consists of > 95% monomers as determined by gel-filtration chromatography.

Biological Activity: PLR’s recombinant mouse leptin antagonist is capable of inhibiting leptin-induced proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor. It also inhibits various leptin effects in several in vitro bioassays. 
Endotoxin: Less than 0.05 ng/µg (0.5 EU/µg) of mouse leptin antagonist. 
Protein content: Protein quantization of recombinant mouse leptin antagonist was carried out by UV spectroscopy at 280 nm using the absorbency value of 0.201 as the extinction coefficient for a 0.1% (1mg/ml) solution at pH 8.0. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).  
Usage: PLR's recombinant mouse leptinantagonist is furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals. It is for Research Purposes Only – Commercial Use has been Licensed Exclusively to a Third Party. 
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